Scientific American Supplement No 803

[Illustration] SCIENTIFIC AMERICAN SUPPLEMENT NO. 803 NEW YORK, May 23, 1891 Scientific American Supplement. Vol. XXXI., No. 803. Scientific American established 1845 Scientific American Supplement, $5 a year. Scientific American and Supplement, $7 a year. * * * * * TABLE OF CONTENTS. I. ASTRONOMY.–The Great Equatorial of the Paris Observatory.– The new telescope recently put in use in Paris.–Description of the instrument and of its effects.–3 illustrations II. CHEMISTRY.–An Apparatus for Heating Substances in Glass Tubes under Pressure.–By H. PEMBERTON, Jr.–A simple apparatus for effecting this purpose, avoiding risk of personal injury.– 2 illustrations Table of Atomic Weights.–A revised table of atomic weights, giving the results of the last determinations, and designed for every-day use Testing Cement.–A laboratory process for testing Portland cement III. CIVIL ENGINEERING.–The Compressed Air System of Paris. –An elaborate review of this great installation for the transmission of power.–The new compressed air station, with full details of performances of apparatus, etc.–10 illustrations IV. ENTOMOLOGY.–Report on Insects.–Continuation of this report on noxious insects.–Their habits and how to cope with them. –18 illustrations V. FLORICULTURE.–Lily of the Valley.–Practical notes on the cultivation of this popular flower.–How to raise it and force the growth VI. MATHEMATICS.–The Conic Sections.–By Prof. C.W. MACCORD.–Examination of the four conic sections with a general definition applicable to all.–6 illustrations VII. MECHANICAL ENGINEERING.–The Builders of the Steam Engine–The Founders of Modern Industries and Nations.–By Dr. R.H. THURSTON.–Prof. Thurston’s address before the Centennial Celebration of the American Patent System at Washington, D.C.–The early history of the steam engine and its present position in the world VIII. MISCELLANEOUS.–The Breeds of Dogs.–Popular description of the different breeds of dogs most affected by amateurs.–6 illustrations IX. NAVAL ENGINEERING.–Modern Armor.–By F.R. BRAINARD.–The development of modern ship armor, from laminated sandwiched and compound types to the present solid armor.–9 illustrations X. PISCICULTURE.–Restocking the Seine with Fish.–The introduction of 40,000 fry of California trout and salmon, designed to restock the Seine, depopulated of fish by explosions of dynamite used in breaking up the ice.–1 illustration XI. RAILWAY ENGINEERING.–Improved Hand Car.–A novelty in the construction of hand cars, avoiding the production of a dead center.–1 illustration XII. TECHNOLOGY.–The Tanning Materials of Europe.–The natural tanning materials and pathological or abnormal growth tanning materials described and classified, with relative power * * * * * THE GREAT EQUATORIAL OF THE PARIS OBSERVATORY. The great instrument which has just completed the installation of our national observatory is constructed upon the same principle as the elbowed equatorial, 11 in. in diameter, established in 1882, according to the ingenious arrangement devised as long ago as 1872, by Mr. Loewy, assistant director of the Paris Observatory. We shall here recall the fact that the elbowed equatorial consists of two parts joined at right angles. One of these is directed according to the axis of the world, and is capable of revolving around its own axis, and the other, which is at right angles to it, is capable of describing around the first a plane representing the celestial equator. At the apex of the right angle there is a plane mirror of silvered glass inclined at an angle of 45 deg. with respect to the optical axis, and which sends toward the ocular the image coming from the objective and already reflected by another and similar plane mirror. The objective and this second mirror (which is inclined at an angle of 45 deg.) are placed at the extremity of the external part of the tube, and form part of a cube, movable around the axis of the instrument at right angles with the axis of the world. The diagram in Fig. 3 will allow the course of a luminous ray coming from space to be easily understood. The image of the star, A, toward which the instrument is directed, traverses the objective, B C, is reflected first from the mirror, B D, and next from the central mirror, E F, and finally reaches O, at the ocular where the observer is stationed. This new equatorial differs from the first model by its much larger dimensions and its extremely remarkable mechanical improvements. The optical part, which is admirably elaborated, consists of a large astronomical objective 24 in. in diameter, and of a photographic objective of the same aperture, capable of being substituted, one for the other, according to the nature of the work that it is desired to accomplish by the aid of this colossal telescope, the total length of which is 59 ft. The two plane mirrors which complete the optical system have, respectively, diameters of 34 in. and 29 in. These two magnificent objectives and the two mirrors were constructed by the Brothers Henry, whose double reputation as astronomers and opticians is so universally established. The mechanical part is the successful work of Mr. Gautier, who has looked after every detail with the greatest care, and has thus realized a true chef d’oeuvre. The colossal instrument, the total weight of which is 26,400 lb., is maneuvered by hand with the greatest ease. A clockwork movement, due to the same able manufacturer, is capable, besides, of moving the instrument with all the precision desirable, and of permitting it to follow the stars in their travel across the heavens. A star appearing in the horizon can thus be observed from its rising to its setting. The astronomer, his eye at the ocular, is always conveniently seated at the same place, observing the distant worlds, rendered immovable, so to speak, in the field of the instrument. For stars which, like the moon and the planets, have a course different from the diurnal motion, it is possible to modify the running of the clockwork, so that they can thus be as easily followed as in the preceding case. Fig. 1 gives a general view of the new installation, for which it became necessary to build a special edifice 65 ft. in height on the ground south of the observatory bordering on the Arago Boulevard. A large movable structure serves for covering the external part of the instrument. This structure rests on rails, upon which it slides toward the south when it is desired to make observations. It will be seen from the figure how the principal axis of the instrument rests upon the two masonry pillars, one of which is 49 ft. and the other 13 ft. in height. [Illustration: FIG 1.–THE GREAT EQUATORIAL OF THE PARIS OBSERVATORY.] The total cost of the pavilion, rolling structure, and instrument (including the two objectives) will amount to about $80,000 after the new equatorial has been provided with the scientific apparatus that necessarily have to accompany it for the various and numerous applications to which the use of it will give rise. [Illustration: FIG 2.–OCULAR OF THE GREAT EQUATORIAL.] Fig. 2 shows us the room in the observatory in which the astronomer, seated in his chair, is completely protected against the inclemencies of the weather. Here, with his eye applied to the ocular, he can, without changing position (owing to all the handles that act at his will upon the many transmissions necessary for the maneuvering), direct his instrument unaided toward every point of the heavens with wonderful sureness and precision. The observer has before him on the same plane two divided circles, one of which gives the right ascensions and the other the declinations, and which he consults at each observation for the exact orientation of the equatorial. [Illustration: FIG. 3.–DIAGRAM SHOWING THE COURSE OF A LUMINOUS RAY IN THE GREAT EQUATORIAL.] All the readings are done by the aid of electric lamps of very small dimensions, supplied by accumulators, and which are lighted at will. Each of these lamps is of one candle power; two of them are designed for the reading of the two circles of right ascension and of declination; a third serves for the reading of the position circle of the micrometer; two others are employed for the reading of the drums fixed upon the micrometric screws; four others serve for rendering the spider threads of the reticule brilliant upon a black ground; and still another serves for illuminating the field of the instrument where the same threads remain black upon a luminous ground. The currents that supply these lamps are brought over two different circuits, in which are interposed rheostats that permit of graduating the intensity of the light at will. Since the installation of the first model of an elbowed equatorial of 11 in. aperture, in 1882, at the Paris Observatory, the numerous and indisputable advantages of this sort of instrument have led a certain number of observatories to have similar, but larger, instruments constructed. In France, the observatories of Alger, Besancon, and Lyons have telescopes of this kind, the objectives of which have diameters of from 12 in. to 13 in., and which have been used for several years past in equatorial observations of all kinds. The Vienna Observatory has for the last two years been using an instrument of this kind whose objective has an aperture of 15 inches. Another equatorial of the same kind, of 16 in. aperture, is now in course of construction for the Nice Observatory, where it will be especially employed as a seeker of exceptional power–a role to which this kind of instrument lends itself admirably. The optical part of all these instruments was furnished by the Messrs. Henry, and the mechanical part by Mr. Gautier. The largest elbowed equatorial is, therefore, that of the Paris Observatory. Its optical power, moreover, corresponds perfectly to its huge dimensions. The experimental observations which have already been made with it fully justify the hopes that we had a right to found upon the professional skill of the eminent artists to whom we owe this colossal instrument. The images of the stars were given with the greatest sharpness, and it was possible to study the details of the surface of the moon and other planets, and several star clusters, in all their peculiarities, in the most remarkable manner. When it shall become possible to make use of this equatorial for celestial photography, there is no doubt that we shall obtain the most important results. As regards the moon, in particular, the photographing of which has already made so great progress, its direct image at the focus of the large 24 in. photographic objective will have a diameter of 11 in., and, being magnified, will be capable of giving images of more than 3 ft. in diameter.–La Nature. * * * * * LILY OF THE VALLEY. There is no flower more truly and universally popular than the lily of the valley. What can be more delicious and refreshing than the scent of its fragrant flowers? What other plant can equal in spring the attractiveness of its pillars of pure white bells half hidden in their beautiful foliage? There are few gardens without a bed of lily of the valley, but too often the place chosen for it is some dark corner where nothing else would be expected to grow, but it is supposed as a matter of course that “it will do for a lily bed.” The consequence is that although these lilies are very easy things to cultivate, as indeed they ought to be, seeing that they grow wild in the woods of this and other countries, yet one hears so often from those who take only a slight interest in practical gardening, “I have a lily bed, but I scarcely ever get any lilies.” Wild lilies are hardly worth the trouble of gathering, they are so thin and poor; it is interesting to find a plant so beautiful and precious in the garden growing wild in the woods, but beyond that the flowers themselves are worth but very little. This at once tells us an evident fact about the lily of the valley, viz., that it does require cultivation. It is not a thing to be left alone in a dark and dreary corner to take care of itself anyhow year after year. People who treat it so deserve to be disappointed when in May they go to the lily bed and find plenty of leaves, but no flowers, or, if any, a few poor, weak attempts at producing blossoms, which ought to be so beautiful and fragrant. One great advantage of this lovely spring flower is that it can be so readily and easily forced. Gardeners in large places usually spend several pounds in the purchase of crowns and clumps of the lily of the valley, which they either import direct from foreign nurserymen or else procure from their own dealer in such things, who imports his lilies in large quantities from abroad. But we may well ask, Have foreign gardeners found out some great secret in the cultivation of this plant? Or is their climate more suitable for it? Or their soil adapted to growing it and getting it into splendid condition for forcing? It is impossible that the conditions for growing large and fine heads of this lily can be in any way better in Berlin or elsewhere than they are in our own land, unless greater heat in summer than we experience in England is necessary for ripening the growths in autumn. There is another question certainly as to varieties; one variety may be superior to another, but surely if so it is only on the principle of the survival of the fittest, that is to say, by carefully working on the finest forms only and propagating from them, a strong and vigorous stock may be the result, and this stock may be dignified with a special name. For my own part what I want is to have a great abundance of lily of the valley from February till the out-door season is over. To do this with imported clumps would, of course, be most costly, and far beyond what any person ought to spend on mere flowers. Though it must be remembered that it is an immense advantage to the parish priest to be able to take bright and sweet flowers to the bedside of the sick, or to gratify the weary spirit of a confirmed invalid, confined through all the lovely spring time to the narrow limits of a dull room, with the fragrant flowers of the lily of the valley. I determined, therefore, that I would have an abundance of early lilies, and that they should not be costly, but simply produced at about the same expense as any other flowers, and I have been very successful in accomplishing this by very simple means. First of all, it is necessary to have the means of forcing, that is to say the required heat, which in my case is obtained from an early vinery. I have seen lilies forced by pushing the clumps in under the material for making a hot bed for early cucumbers, the clumps being drawn out, of course, as soon as the flowers had made a good start. They have then to be carefully and very gradually exposed to full light, but often, although fine heads of bloom may be produced in this way, the leaves will be few and poor. My method is simply this: In the kitchen garden there is the old original bed of lilies of the valley in a corner certainly, but not a dark corner. This is the reservoir, as were, from whence the regular supply of heads for special cultivation is taken. This large bed is not neglected and left alone to take care of itself, but carefully manured with leaf mould and peat moss manure from the stable every year. Especially the vacant places made by taking out the heads for cultivation are thus filled up. Then under the east wall another piece of ground is laid out and divided into four plots. When I first began to prepare for forcing I waited four years, and had one plot planted with divided heads each year. Clumps are taken up from the reserve bed and then shaken out and the heads separated, each with its little bunch of fibrous roots. They are then carefully planted in one of the plots about 4 in. or 5 in. apart, the ground having previously been made as light and rich as possible with plenty of leaf mould. I think the best time for doing this is in autumn, after the leaves have turned yellow and have rotted away; but frequently the operation has been delayed till spring, without much difference in the result. Asparagus is usually transplanted in spring, and there is a wonderful affinity between the two plants, which, of course, belong to the same order. It was a long time to wait–four years–but I felt there was no use in being in too great a hurry, and every year the plants manifestly improved, and the buds swelled up nicely and looked more plump each winter when the leaves were gone. It must be remembered also that a nice crop of flowers could be gathered each year. When the fourth year came, the first plot was divided up into squares about 2 ft. each way, and taken up before any hard frost or snow had made their appearance, and put away on the floor of an unused stable. From the stable they are removed as required in the squares to the vinery, where they grow beautifully, not sending up merely fine heads of bloom without a vestige of leaf, but growing as they would in spring out of doors with a mass of foliage, among which one has to search for the spikes of flower, so precious for all sorts of purposes at that early season of the year. The spikes produced in this way do not equal in thickness and substance of petal the flowers which come from more carefully prepared clumps imported from Berlin, but they are fine and strong, and above all most abundant. I can not only supply the house and small vases for the church, but also send away boxes of the flowers to friends at a distance, besides the many gifts which can be made to those who are ill or invalids. Few gifts at such a time are more acceptable than a fragrant nosegay of lily of the valley. In order to keep the supply of prepared roots ready year after year, a plot of ground has only to be planted each autumn, so that in the rotation of years it may be ready for forcing when its turn shall come. As the season advances, as every one knows who has attempted to force the lily of the valley, much less time is taken in bringing the flowers to perfection under precisely the same circumstances as those in which the first sods are forced. In February or earlier the buds are more unwilling to start; there seems to be a natural repugnance against being so soon forced out of the winter’s sleep and rest. But when the flowers do come, they are nearly as fine and their leaves are quite as abundant in this way of forcing as from the pieces introduced much later into heat. It would be easy to preserve the squares after all the flowers are gathered, but I found that they would not, like strawberries, kindly furnish forth another crop later on in the year, and, therefore, mine are flung away; and I have often pitied the tender leaves in the frost and snow after their short sojourn in the hot climate of the vinery. But the reserve bed will always supply an ample quantity of fresh heads, and it is best to take the new plants for preparation in the kitchen garden from this reserve bed. This very simple method of forcing lilies of the valley is within the reach of any one who has even a small garden and a warm house, and these two things are becoming more and more common among us every day.–A Gloucestershire Parson, in The Garden. * * * * * [Continued from SUPPLEMENT, No. 802, page 12820.] REPORT ON INSECTS. THE ONION MAGGOT. Phorbia ceparum (Meig.) Early in June a somewhat hairy fly, Fig. 9, may be seen flying about, and depositing its eggs on the leaves of the young onion plants, near the roots, Fig. 10. [Illustration: FIG. 9.] Dr. Fitch describes this fly as follows: “It has a considerable resemblance to the common house fly, though when the two are placed side by side, this is observed as being more slender in its form. The two sexes are readily distinguished from each other by the eyes, which in the males are close together, and so large as to occupy almost the whole surface of the head, while in the females they are widely separated from each other. These flies are of an ash gray color, with the head silvery, and a rusty black stripe between the eyes, forked at its hind end. And this species is particularly distinguished by having a row of black spots along the middle of the abdomen or hind body, which sometimes run into each other, and then forming a continuous stripe. “This row of spots is quite distinct in the male, but in the female is very faint, or is often wholly imperceptible. This fly measured 0.22 to 0.25 inch in length, the females being usually rather larger than the males.” The eggs are white, smooth, somewhat oval in outline, and about one twenty-fifth of an inch in length. Usually not more than half a dozen are laid on a single plant, and the young maggot burrows downward within the sheath, leaving a streak of pale green to indicate its path, and making its way into the root, devours all except the outer skin. [Illustration: FIG. 10.] The maggots reach their full growth in about two weeks, when they are about one-third of an inch long, white and glossy, tapering from the posterior end to the head, which is armed with a pair of black, hook-like jaws. The opposite end is cut off obliquely and has eight tooth-like projections around the edge, and a pair of small brown tubercles near the middle. Fig. 11 shows the eggs, larva, and pupa, natural size and enlarged. [Illustration: FIG. 11.] They usually leave the onions and transform to pupae within the ground. The form of the pupa does not differ very much from the maggot, but the skin has hardened and changed to a chestnut brown color, and they remain in this stage about two weeks in the summer, when the perfect flies emerge. There are successive broods during the season, and the winter is passed in the pupa stage. The following remedies have been suggested: Scattering dry, unleached wood ashes over the plants as soon as they are up, while they are wet with dew, and continuing this as often as once a week through the month of June, is said to prevent the deposit of eggs on the plants. Planting the onions in a new place as remote as possible from where they were grown the previous year has been found useful, as the flies are not supposed to migrate very far. Pulverized gas lime scattered along between the rows has been useful in keeping the flies away. Watering with liquid from pig pens collected in a tank provided for the purpose, was found by Miss Ormerod to be a better preventive than the gas lime. When the onions have been attacked and show it by wilting and changing color, they should either be taken up with a trowel and burned, or else a little diluted carbolic acid, or kerosene oil, should be dropped on the infested plants to run down them and destroy the maggots in the roots and in the soil around them. Instead of sowing onion seed in rows, they should be grown in hills, so that the maggots, which are footless, cannot make their way from one hill to another. THE CABBAGE BUTTERFLY. Pieris rapae (Linn.) In the New England States there are three broods of this insect in a year, according to Mr. Scudder, the butterflies being on the wing in May, July, and September; but as the time of the emergence varies, we see them on the wing continuously through the season. [Illustration: FIG. 12.] The expanded wings, Fig. 12, male, measure about two inches, are white above, with the base dusky. Both sexes have the apex black and a black spot a little beyond the middle, and the female, Fig. 13, has another spot below this. The under side of the fore wings is white, yellowish toward the apex, and with two black spots in both sexes corresponding to those on the upper side of the female. A little beyond the middle of the costa, on the hind wings, is an irregular black spot on the upper surface, while the under surface is pale lemon yellow without marks, but sprinkled more or less with dark atoms. The body is black above and white beneath. [Illustration: FIG. 13.] The caterpillars of this insect feed on the leaves of cabbage, cauliflower, turnip, mignonette, and some other plants. The female lays her eggs on the under side of the leaves of the food plants, generally, but sometimes on the upper sides or even on the leaf stalks. They are sugar loaf shaped, flattened at the base, and with the apex cut off square at the top, pale lemon yellow in color, about one twenty-fifth of an inch long and one fourth as wide, and have twelve longitudinal ribs with fine cross lines between them. The eggs hatch in about a week, and the young caterpillars, which are very pale yellow, first eat the shells from which they have escaped, and then spin a carpet of silk, upon which they remain except when feeding. They now eat small round holes through the leaves, but as they grow older change to a greenish color, with a pale yellow line along the back, and a row of small yellow spots along the sides, and eat their way down into the head of the cabbage. [Illustration: FIG. 14.] Having reached its full growth, the caterpillar, Fig. 14, a, which is about an inch in length, wanders off to some sheltered place, as under a board, fence rail, or even under the edge of clapboards on the side of a building, where it spins a button of silk, in which to secure its hind legs, then the loop of silk to support the forward part of the body. It now casts its skin, changing to a chrysalis, Fig. 14, b, about three-fourths of an inch in length, quite rough and uneven, with projecting ridges and angular points on the back, and the head is prolonged into a tapering horn. In color they are very variable, some are pale green, others are flesh colored or pale ashy gray, and sprinkled with numerous black dots. The winter is passed in the chrysalis stage. After the caterpillar changes to a chrysalis, their minute parasites frequently bore through the outside and deposit their eggs within. These hatch before the time for the butterflies to emerge, and feeding on the contents, destroy the life of the chrysalis. Birds and spiders are of great service in destroying these insects. The pupae should be collected and burned if the abdomen is flexible; but if the joints of the abdomen are stiff and cannot be easily moved, they should be left, as they contain parasites. Several applications of poisons have been used, the best results being obtained from the use of pyrethrum as a powder blown on to the plants by a hand bellows, during the hottest part of the day, in the proportion of one part to four or five of flour. As the eggs are laid at different times, any application, to be thoroughly tested, must be repeated several times. THE APPLE TREE TENT CATERPILLAR. Clisiocampa Americana (Harr.) Large, white, silken web-like tents, Fig. 15, are noticed by the roadsides, in the early summer, on wild cherry trees, and also on fruit trees in orchards, containing numerous caterpillars of a blackish color, with fine gray hairs scattered over the body. This well known pest has been very abundant throughout the State for several years past, and the trees in many neglected orchards have been greatly injured by it, some being entirely stripped of their leaves. The trees in these orchards and the neglected ones by the roadsides form excellent breeding places for this insect, and such as are of little of no value should be destroyed. If this were well done, and all fruit growers in any given region were to destroy all the tents on their trees, even for a single season, the work of holding them in check or destroying them in the following year would be comparatively light. [Illustration: FIG. 15.] The moths, Fig. 16, appear in great numbers in July, their wings measuring, when expanded, from one and a quarter to one and a half inches or more. They are of a reddish brown color, the fore wings being tinged with gray on the base and middle, and crossed by two oblique whitish stripes. [Illustration: FIG. 16.] The females lay their eggs, about three hundred in number, in a belt, Fig. 15, c, around the twigs of apple, cherry, and a few other trees, the belt being covered by a thick coating of glutinous matter, which probably serves as a protection against the cold weather during winter. The following spring, when the buds begin to swell, the egg hatch and the young caterpillar seek some fork of a branch, where they rest side by side. They are about one-tenth of an inch long, of a blackish color, with numerous fine gray hairs on the body. They feed on the young and tender leaves, eating on an average two apiece each day. Therefore the young of one pair of moths would consume from ten to twelve thousand leaves; and it is not uncommon to see from six to eight nests or tents on a single tree, from which no less than seventy-five thousand leaves would be destroyed–a drain no tree can long endure. As the caterpillars grow, a new and much larger skin is formed underneath the old one, which splits along the back and is cast off. When fully grown, Fig. 15, a and b, which is in about thirty-five to forty days after emerging from the eggs, they are about two inches long, with a black head and body, with numerous yellowish hairs on the surface, with a white stripe along the middle of the back, and minute whitish or yellowish streaks, which are broken and irregular along the sides; and there is also a row of transverse, small, pale blue spots along each side of the back. As they move about they form a continuous thread of silk from a fleshy tube on the lower side of the mouth, which is connected with the silk-producing glands in the interior of the body, and by means of this thread they appear to find their way back from the feeding grounds. It is also by the combined efforts of all the young from one belt of eggs that the tents are formed. These caterpillars do not feed during damp, cold weather, but take two meals a day when it is pleasant. After reaching their full growth, they leave their tents and scatter in all directions, seeking for some protected place where each one spins its spindle-shaped cocoon of whitish silk intermingled with sulphur colored powder, Fig. 15, d. They remain in these cocoons, where they have changed to pupae, from twenty to twenty-five days, after which the moths emerge, pair, and the females lay their eggs for another brood. Several remedies have been suggested, a few of which are given below. Search the trees carefully, when they are bare, for clusters of eggs; and, when found, cut off the twigs to which they are attached, and burn them. As soon as any tents are observed in the orchard they should be destroyed, which may be readily and effectually done by climbing the trees, and with the hand protected by a mitten or glove, seize the tent and crush it with its entire contents; also swab them down with strong soapsuds or other substances; or tear them down with a rounded bottle brush. Burning with a torch not only destroys the caterpillars but injures the trees. It should be observed, however, since the caterpillars, are quite regular in taking their meals, in the middle of the forenoon and afternoon, that they should be destroyed only in the morning or evening, when all are in the tent. Another remedy is to shower the trees with Paris green in water, in the proportion of one pound to one hundred and fifty gallons of water. THE FOREST TENT CATERPILLAR. Clisiocampa disstria (Huebner.) This species, commonly known as the forest tent caterpillar, closely resembles the apple tree tent caterpillar, but does not construct a visible tent. It feeds on various species of forest trees, such as oak, ash, walnut, hickory, etc., besides being very injurious to apple and other fruit trees. The moth, Fig. 17, b, expands an inch and a half or more. The general color is brownish yellow, and on the fore wings are two oblique brown lines, the space between them being darker than the rest of the wing. The eggs, Fig. 17, c and d, which are about one twenty fifth of an inch long and one fortieth wide, are arranged, three or four hundred in a cluster, around the twigs of the trees, Fig. 17, a. These clusters are uniform in diameter and cut off squarely at the ends. The eggs are white, and are firmly fastened to the twigs and to each other, by a brown substance, like varnish, which dries, leaving the eggs with a brownish covering. [Illustration: FIG. 17.] The eggs hatch about the time the buds burst, or before, and the young caterpillars go for some time without food, but they are hardy and have been known to live three weeks with nothing to eat, although the weather was very cold. [Illustration: FIG. 18.] As soon as hatched they spin a silken thread wherever they go, and when older wander about in search for food. The caterpillars are about one and a half inches long when fully grown, Fig. 18. The general color is pale blue, tinged with greenish low down on the sides, and everywhere sprinkled with black dots or points, while along the middle of the back is a row of white spots each side of which is an orange yellow stripe, and a pale, cream yellow stripe below that. These stripes and spots are margined with black. Each segment has two elevated black points on the back, from each of which arise four or more coarse black hairs. The back is clothed with whitish hairs, the head is dark bluish freckled with black dots, and clothed with black and fox-colored hairs, and the legs are black, clothed with whitish hairs. At this stage the caterpillars may be seen wandering about on fences, trees, and along the roads in search of a suitable place to spin their cocoons, which are creamy white, and look very much like those of the common tent caterpillar, except that they are more loosely constructed. Within the cocoons, in two or three days they transform to pupae of a reddish brown color, densely clothed with short pale yellowish hairs. The moths appear in two or three weeks, soon lay their eggs and then die. The insects are not abundant many years in succession, as their enemies, the parasites, increase and check them. Many methods have been suggested for their destruction, but the most available and economical are to remove the clusters of eggs whenever found, and burn them, and to shower the trees with Paris green in the proportion of one pound to one hundred and fifty gallons of water. THE STALK BORER. Gortyna nitela (Gruen.) The perfect moth, Fig. 19, 1, expands from one to one and a half inches. The fore wings are a mouse gray color, tinged with lilac and sprinkled with fine yellow dots, and distinguished mainly by a white band extending across the outer part. The moths hibernate in the perfect state, and in April or May deposit their eggs singly on the outside of the plant upon which the young are to feed. As soon as the eggs hatch, which is in about a month, the young larvae, or caterpillars, gnaw their way from the outside into the pith. [Illustration: FIG. 19.] The plant does not show any sign of decay until the caterpillar is fully grown, when it dies. The caterpillar, Fig. 19, 2, is about one and one-fourth inches long, of a reddish brown color, with whitish stripes along the body. The stripes on the sides are not continuous, and the shading of the body varies, being darker on the anterior than on the posterior portion. When fully grown, Fig. 20, the color is lighter and the stripes are broader. At this stage of life it burrows into the ground just beneath the surface, and changes into the pupa state. The pupa is three-fourths of an inch long, and of a mahogany brown color. The perfect moth appears about the first of September, and there is only one brood in a season. [Illustration: FIG. 20.] The caterpillars feed in the stalks of corn, tomatoes, potatoes, dahlias, asters, and also in young currant bushes, besides feeding on many species of weeds. By a close inspection of the plants about the beginning of July, the spot where the borer entered, which is generally quite a distance from the ground, may be detected, and the caterpillar cut out without injury to the plant. This plan is impracticable for an extensive crop, but by destroying the borers found in the vines that wilt suddenly, one can lessen the number another year. THE PYRAMIDAL GRAPEVINE CATERPILLAR. Pyrophila pyramidoides (Guen.) This caterpillar, Fig. 21, is generally found on grapevines early in June, but also feeds on apple, plum, raspberry, maple, poplar, etc. It is about an inch and a half in length, with the body tapering toward the head; of a whitish green color, darker on the sides; with a longitudinal white stripe on the back, broader on the last segments. Low down on each side is a bright yellow stripe, between this and the one on the back is another less distinct, and the under surface of the body is pale green. [Illustration: FIG. 21.] The caterpillar is fully grown about the middle or last of June, when it descends to the ground, draws together some of the fallen leaves, and makes a cocoon, in which it soon changes to a mahogany brown pupa. [Illustration: FIG. 22.] In the latter part of July the perfect moth, Fig. 22, emerges, measuring, when its wings are expanded, about one and three-fourths inches; the fore wings are dark brown shaded with lighter, with dots and wavy lines of dull white. The hind wings are reddish, or of a bright copper color, shading to brown on the outer angle of the front edge of the wing, and paler toward the hinder and inner angle. The under surface of the wings is lighter than the upper, and the body is dark brown, with its posterior portion banded with lines of a paler hue. This pest may be destroyed by hand picking, or by jarring the trees or vines on which they are feeding, when they will fall to the ground and may be crushed or burned. THE GRAPE BERRY MOTH. Eudemis botrana (S.V.) The moths emerge and fly early in June, and are quite small, measuring, when the wings are expanded, only two-fifths of an inch, Fig. 23, a, enlarged. The fore wings are purplish or slate brown from the base to the middle, the outer half being irregularly marked with dark and light brown. [Illustration: FIG. 23.] These insects are two-brooded and the first brood feeds not only on the leaves of the grape, but on tulip, sassafras, vernonia and raspberry. The caterpillars of the second brood emerge when the grapes are nearly grown, and bore in them a winding channel to the pulp, continuing to eat the interior of the berry till the pulp is all consumed, Fig. 23, d, when, if not full grown, they draw one or two other berries close to the first and eat the inside of those. The mature caterpillar, Fig. 23, b, measures about half an inch in length, is dull greenish, with head and thoracic shield somewhat darker; the internal organs give the body a reddish tinge. It then leaves the grape and forms its cocoon by cutting out a piece of a leaf, leaving it hinged on one side; then rolling the cut end over, fastens it to the leaf, thus making for itself a cocoon in which to pupate. The pupa is dark reddish brown. The second generation passes the winter in the pupa state, attached to leaves which fall to the ground; therefore, if all the dead and dried leaves be gathered in the fall and burned, also all the decayed fruit, a great many of these insects would be destroyed. As the caterpillars feed inside of the berry, no spraying of the vines with poisons would reach them. The caterpillar makes a discolored spot where it enters the berry, Fig. 23, c. Therefore the infested fruit may be easily detected and destroyed. There is a small parasite that attacks this insect and helps to keep it in check. The insect has been known in Europe over a hundred years. It is not certain when it was introduced into America, but it is now found from Canada to the Gulf of Mexico, and from the Atlantic to the Pacific Ocean. THE CODLING MOTH. Carpocapsa pomonella (Linn.) This well known insect has a world-wide reputation, and is now found wherever apples are raised. [Illustration: FIG. 24.] The moths are on the wing about the time the young apples are beginning to set, and the female lays a single egg in the blossom end of each apple. The fore wings of the moths when expanded, Fig. 24, g (f, with the wings closed), measure about half an inch across, and are marked with alternate wavy, transverse streaks of ashy gray and brown, and have on the inner hind angle a large tawny brown, horseshoe shaped spot, streaked with light bronze or copper color. The hind wings and abdomen are light brown with a luster of satin. Each female lays about fifty eggs, which are minute, flattened, scale-like bodies of a yellowish color. In about a week the eggs hatch and the tiny caterpillar begins to eat through the apple to the core, Fig. 24, a, pushing its castings out through the hole where it entered, Fig. 24, b. Oftentimes these are in sight on the outside in a dark colored mass, thus making wormy apples plainly seen at quite a distance. The caterpillar is about two-fifths of an inch in length, of a glossy, pale yellowish white color, with a light brown head. The skin is transparent and the internal organs give to it a reddish tinge. When mature the caterpillars, Fig. 24, e, top of head and second segment, h, emerge from the apples and seek some sheltered place, such as crevices of bark, or corners of the boxes or barrels in which the fruit is stored, where they spin a tough whitish cocoon, Fig. 24, i, in which they remain unchanged all winter, and transform to pupae, Fig. 24, d, the next spring, the perfect moths emerging in time to lay their eggs in the new crop of apples. One good remedy is to gather all the fallen apples, and feed them to hogs; another is to let swine and sheep run in the orchard, and eat the infested fruit. It has been recommended to place bands of cloth or hay around the trunks of the trees for the caterpillars to spin their cocoons beneath, and to remove them at the proper time, and put them in scalding water to destroy the worms. By far the most successful method as yet adopted is to shower the apple trees with Paris green in water, one pound to one hundred and fifty gallons of water, when the apples are about the size of peas, and again in about a week. THE CABBAGE LEAF MINER. Plutella cruciferarum (Zell.) The cabbage leaf miner is not a native of this country, but was imported from Europe. [Illustration: FIG. 25.] The perfect moth, Fig. 25, f, with the wings expanded (h, with the wings closed, g, a dark variety), measures three-quarters of an inch. The fore wings are ashy gray, and on the hinder margin is a white or yellowish white stripe having three points extending into the gray, thus forming, when the wings are closed, three diamond-shaped white spots. Generally there is a dark brown stripe between the white and the gray. There are also black dots scattered about on the anterior part of these wings. The hind wings are leaden brown, and the under side of all the wings is leaden brown, glossy, and without any dots. The antennae are whitish with dark rings, and the abdomen white. There are two broods of this insect in this region, the moths of the first appearing in May, and those of the second in August. They hibernate in the pupa stage. The caterpillars, Fig. 25, a (b, the top and c, the side of a segment), appear in June or July and September; they are small and cylindrical, tapering at both ends, pale green, and about one-fourth of an inch long. The head has a yellowish tinge, and there are several dark stiff hairs scattered over the body. When ready to transform, this caterpillar spins a delicate gauze-like cocoon, Fig. 25, e, made of white, silken threads, on the under side of a cabbage leaf. The pupa, Fig. 25, d, and i, the end of a pupa, is commonly white, sometimes shaded with reddish brown, and can be distinctly seen through the silken case. The first brood is more injurious than the second, as it feeds on the young cabbage leaves before the head is formed, and this must surely stunt the growth and make weak, sickly plants; while the second brood feeds only on the outside leaves. The caterpillars are very active, wriggling violently when disturbed, and falling by a white silken thread. Hot dry weather is favorable to them and enables them to multiply rapidly. Advantage has been taken of this fact, and spraying the plants thoroughly with water is strongly recommended. Prof. Riley states that the insects are very readily destroyed by pyrethrum. There are two species of spiders and a species of ichneumon fly that destroy them. THE GARTERED PLUME MOTH. Oxyptilus periscelidactylus (Fitch.) The caterpillars of this species draw together the young grape leaves, Fig. 26, a, in the spring, with fine silken threads, and feed on the inside, thus doing much damage in proportion to their size. These caterpillars, Fig. 26, a, and e, a segment greatly enlarged, are full grown in about two weeks, when they are about one-fourth of an inch long, pale green with whitish hairs arising from a transverse row of warts on each segment. Early in June they transform to pupae, Fig. 26, b, which are pale green at first and change to dark brown. The surface is rough and the head is cut off obliquely, while on the upper side near the middle are two sharp pointed horns, Fig. 26, c. They remain in this stage from a week to ten days, when the moths emerge. [Illustration: FIG. 26.] The moths, Fig. 26, d, belong to the family commonly known as plume moths or feather wings (Pterophoridae), from having their wings divided into feather-like lobes. When the wings are expanded they measure about seven-tenths of an inch across. They are yellowish brown with a metallic luster, and have several dull whitish streaks and spots. The fore wings are split down the middle about half way to their base, the posterior half having a notch in the outer margin. The body is somewhat darker than the wings. It is not known positively in what stage the winter is passed, but it is supposed to be the perfect, or imago stage. The unnatural grouping and spinning of the leaves together leads to their detection, and they can be easily destroyed by hand picking and then crushing or burning them. * * * * * THE BREEDS OF DOGS. The dog exhibitions that have annually taken place for the last eight years at Paris and in the principal cities of France have shown how numerous and varied the breeds of dogs now are. It is estimated that there are at present, in Europe, about a hundred very distinct and very fine breeds (that is to say, such as reproduce their kind with constant characters), without counting a host of sub-breeds or varieties that a number of breeders are trying to fix. Most of the breeds of dogs, especially those of modern creation, are the work of man, and have been obtained by intercrossing older breeds and discarding all the animals that departed from the type sought. But many of these breeds are also the result of accident, or rather of modifications of certain parts of the organism–of a sort of rachitic or teratological degeneration which has become hereditary and has been due to domestication; for it is proved that the dog is the most anciently domesticated animal, and that its submission to man dates back to more than five thousand years. Such is the origin of the breeds of terriers, bulldogs, and all of the small house dogs. Man has often, designedly or undesignedly, aided in the production of breeds of this last category by submitting the dog to a regimen contrary to nature, or setting to work to reproduce an animal born monstrous, either for curiosity or for interest. As well known, the accidental characters and the spontaneous modifications which work no injury to the essential functions of life became easily hereditary, and the same is the case with certain artificial modifications pursued for a long series of generations. It was the opinion of Buffon that the breeds of dogs, which were already numerous in his time, were all derived from a single type, which, according to him, was the shepherd’s dog. Other scientists have insisted that the dog descended from the wolf, and others from the jackal. At the present time, it is rightly admitted that several species of wild dogs have concurred in the formation of the different breeds of dogs as we now have them. In the lacustrine habitations of the stone age in Sweden, and in the kjoekkenmoedding (kitchen remains) of Denmark, of the same epoch, we find the remains of a dog, which, according to Rutymeyer, belongs to a breed which is constant up to its least details, and which is of a light and elegant conformation, of medium size, with a spacious and rounded cranium and a short, blunt muzzle, and a medium sized jaw, the teeth of which form a regular series. This dog, which has been named by geologists Canis palustris, fully resembles in size, slenderness of the limbs, and weakness of the muscular insertions, the spaniel, the brach hound, or the griffon. This dog of the stone age is entirely distinct from the wolf and jackal, of which some regard the domestic dog as a descendant, and as it has appeared in Denmark as well as in Sweden, there is no doubt that this species, peculiar to Europe, was subjugated by man and used by him, in the first place, for hunting, and later on for guarding houses and cattle. Later still, in the age of metals, we observe the appearance, both in Denmark and Sweden, of larger and stronger breeds of dogs, having in their jaws the character of mastiffs, and probably introduced by the first emigrants from Asia. There are, moreover, historic proofs that the dogs of the strongest breeds are indigenous to Asia, where we still find the dog of Thibet, the most colossal of all; in fact, in Pliny we read the following narrative: Alexander the Great received from a king of Asia a dog of huge size. He wished to pit it against bears and wild boars, but the dog remained undisturbed and did not even rise, and Alexander had it killed. On hearing of this, the royal donor sent a second dog like the first, along with word that these dogs did not fight so weak animals, but rather the lion and the elephant, and that he had only two of such individuals, and in case that Alexander had this one killed, too, he would no longer find his equal. Alexander matched this dog with a lion and then with an elephant, and he killed them both. Alexander was so afflicted at the premature death of the first dog, that he built a city and temples in honor of the animal. Did the mountainous province of Epirus called Molossia, in ancient Greece, give its name to the molossi that it produced, or did these large dogs give their name to the country? At all events, we know that it was from Epirus that the Romans obtained the molossi which fought wild animals in the circuses, and that from Rome they were introduced into the British islands and have became the present mastiffs. Although our hunting and shepherd’s dogs have a European and the mastiffs an Asiatic ancestry, the ancestry of the harriers is African, and especially Egyptian; in fact, in Upper Egypt we find a sort of large white jackal (Simenia simensis) with the form of a harrier, and which Paul Gervais regarded with some reason as the progenitor of the domestic harrier, and a comparison of their skulls lends support to this opinion. A study of the most ancient monuments of the Pharaohs shows that the ancient Egyptians already had at least five breeds of dogs: two very slim watch dogs, much resembling the harrier, a genuine harrier, a species of brach hound and a sort of terrier with short and straight legs. All these dogs had erect ears, except the brach, in which these organs were pendent, and this proves that the animal had already undergone the effects of domestication to a greater degree than the others. The harrier of the time of the Pharaohs still exists in great numbers in Kordofan, according to Brehm. Upon the whole, we here have, then, at least three stocks of very distinct dogs: 1, a hunting or shepherd’s dog, of European origin; 2, a mastiff, typical of the large breed of dogs indigenous to Asia; and 3, a harrier, indigenous to Africa. We shall not follow the effects of the combination of these three types through the ages, and the formation of the different breeds; for that we shall refer our readers to a complete work upon which we have been laboring for some years, and two parts of which have already appeared.[1] [Footnote 1: Les Races des Chiens, in La Bibliotheque de l’Eleveur.] We shall rapidly pass in review the different breeds of dogs that one may chance to meet with in our dog shows, beginning with the largest. It is again in mountainous countries that the largest dogs are raised, and the character common to all of these is a very thick coat. The largest of all, according to travelers, is the Thibetan dog. Buffon tells of having seen one which, when seated, was five feet in height. One brought back by the Prince of Wales from his voyage to the Indies was taller in stature, stronger and more stocky than a large mastiff, from which it differed, moreover, in its long and somewhat coarse hair, which was black on the back and russet beneath, the thighs and the tail being clothed with very long and silky hair. In France, we have a beautiful mountain dog–the dog of the Pyrenees–which is from 32 to 34 inches in height at the shoulders, and has a very thick white coat, spotted above with pale yellow or grayish fox color. It is very powerful, and is capable of successfully defending property or flocks against bears and wolves. The Alpine dog is the type of the mountain dog. It is of the same size as the dog of the Pyrenees, and differs therefrom especially in its coloring. It is white beneath, with a wide patch of orange red covering the back and rump. The head and ears are of the same color, with the addition of black on the edges; but the muzzle is white, and a stripe of the same color advances upon the forehead nearly up to the nape of the neck. The neck also is entirely white. There are two varieties of the Alpine or St. Bernard dog, one having long hair and the other shorter and very thick hair. We give in Fig. 1 a portrait of Cano, a large St. Bernard belonging to Mr. Gaston Leonnard. [Illustration: FIG. 1–LARGE ST. BERNARD DOG BELONGING TO MR. LEONARD.] Although this breed originated at the celebrated convent of St. Bernard, it no longer exists there in a state of purity, and in order to find fine types of it we have to go to special breeders of Switzerland and England. The famous Plinnlimon, which was bought for $5,000 by an American two or three years ago, and about which there was much talk in the papers, even the political ones, was born and reared in England. It appears that it is necessary, too, to reduce the number of life-saving acts that it is said are daily performed by the St. Bernard dogs. This is no longer but a legend. There was, it is true, a St. Bernard named Barry, now exhibited in a stuffed state in the Berne Museum, which accomplished wonders in the way of saving life, but this was an exception, and the reputation of this animal has extended to all others of its kind. These latter are simply watch dogs kept by the monks for their own safety, and which do not go at all by themselves alone to search for travelers that have lost their way in the snow. The Newfoundland dog, which differs from the preceding in its wholly black or black and white coat, was, it appears, also of mountain origin. According to certain authors, it is indigenous to Norway, and was carried to Newfoundland by the Norwegian explorers who discovered the island. Adapted to their new existence, they have become excellent water dogs, good swimmers, and better life savers by far than the majority of their congeners. Is it from descending to the plain that the mountain dogs have lost their long hair and have become short haired dogs like the English dog or mastiff and the German or large Danish dogs? It is very probable. At all events, it is by this character of having short hair that mastiffs are distinguished from the mountain dogs. Again, the large breed of dogs are distinguished from each other by the following characters: The mastiff is not very high at the shoulders (30 inches), but he is very heavy and thick set, with powerful limbs, large head, short and wide muzzle and of a yellowish or cafe-au-lait color accompanying a black face; that is to say, the ears, the circumference of the eyes and the muzzle are of a very dark color. The German or large Danish dogs constitute but one breed, but of three varieties, according to the coat: (1) those whose coat is of a uniform color, say a slaty gray or isobelline of varying depth, without any white spots; (2) those having a fawn colored coat striped transversely with black like the zebra, but much less distinctly; (3) those having a spotted coat, that is to say, a coat with a white ground strewed with irregular black spots of varying size. These, like those of the first variety are generally small-eyed. Whatever be the variety to which they belong, the German or large Danish dogs are slimmer than, and not so heavy as, the mastiffs. Some, even, are so light that it might be supposed that they had some heavier blood in their veins. They have also a longer muzzle, although square, and are quicker in gait and motions. The largest dogs are to be met with in this breed, and the beautiful Danish dog belonging to Prof. Charcot (Fig. 2) is certainly the largest dog in France and perhaps in Europe. It measures 36 inches at the shoulders and has an osseous and muscular development perfectly in keeping with its large stature, and at the same time has admirable proportions and lightness, and its motions are comparable to those of the finest horse. [Illustration: FIG. 2–DR. CHARCOT’S LARGE DANISH DOG.] Among the English dogs or mastiffs, we very frequently meet with individuals in which the upper incisors and canines are placed back of the corresponding ones in the lower jaw, this being due to a slight shortening of the bones of the upper jaw, not visible externally. This is the first degree of an artist of teratological development, which, since the middle ages, has become very marked in certain subjects, and has given rise to a variety in which this defect has become hereditary. Such is the origin of the breed of bulldogs. The latter were originally as large as the mastiffs. Carried to Spain under Philip II., they have there preserved their primitive characters, but the bulldogs remaining in England have continued to degenerate, so that now the largest are scarcely half the size of the Spanish bulldog, and the small ones attain hardly the size of the pug, although they preserve considerable width of chest and muscular strength. POINTERS. Man hunted for ages with dogs that he united in a pack; but these packs were of a very heterogeneous composition, since they included strong dogs, light dogs very swift of foot, shepherds’ dogs, and others noted for acuteness of scent, and even mongrels due to a crossing with the wolf. It is from the promiscuousness of all these breeds that has arisen our ordinary modern dog. The pointer is of relatively recent creation, and is due to the falconers. In our western countries, falconry dates from the fourth and fifth centuries, as is proved by the capitularies of Dagobert. This art, therefore, was not brought to us from the East by the crusaders in the twelfth and thirteenth centuries, as stated by Le Maout in his Natural History of Birds. The falconer soon saw the necessity of having a dog of nice scent having for its role the finding or hunting up of game without pursuing it, in order to permit the falcons themselves to enter into the sport. This animal was called the bird dog, and was regarded as coming from various countries, especially from Spain, whence the name of spaniel that a breed of pointers has preserved. It is quite curious to find that for three or four centuries back there have been no spaniels in Spain. From Italy also and from southern climes comes what is called the bracco, whence doubtless is derived the French name braque and English brach. Finally the agasse of the Bretons was certainly also one of the progenitors of our present pointers. It was, says Oppian, a breed of small and very courageous dogs, with long hair, provided with strong claws and jaws, that followed hares on the sly under shelter of vine-stocks and reeds and sportively brought them back to their masters after they had captured them. We have certainly here the source of our barbets and griffons. Finally the net hunters of the middle ages also contributed much to the creation of the pointer, for it is to them that we owe the setter. It is erroneously, in fact, that certain authors have attributed the creation of this dog to hunters with the arquebuse, since this weapon did not begin to be utilized in hunting until the sixteenth century. Gaston Phoebus, who died in 1391, shows, in his remarkable work, that the net hunters made use of Spanish setters and that it was they who created the true pointer–the animal that fascinates game by its gaze. By the same pull of their draw net they enveloped in its meshes both the setter and the prey that it held spellbound. Upon the whole, we see that at the end of the middle ages there existed three types of pointers: spaniels, brachs and very hairy dogs, that Charles Estienne, in his Maison Rustique, of the sixteenth century, calls barbets. It is again with these three types that are connected all the present pointers, which we are going to pass rapidly in review. The Brach hounds.–To-day we reserve the name of brachs for all pointers with short hair. The type of the old brach still exists in Italy, Spain, the south of France and in Germany. It is characterized by its large size, its robust form, its large head, its long, flat ears, its square muzzle separated from the forehead by a deep depression, its large nose, often double (that is to say, with nostrils separated by a deep vertical groove), its pendent lips, its thick neck, its long and strong paws provided with dew claws, both on the fore and the hind feet, and its short hair, which is usually white and marked with brown or orange-yellow spots. The old brach breed has been modified by the breeders of different countries, either by hygiene or by crossing with ordinary dogs, according to the manner of hunting, according to taste, and even according to fashion. Thus in England, where “time is money” reigns in every thing and where they like to hunt quickly and not leisurely, the brach has been rendered lighter and swifter of foot and has become the pointer. In France, while it has lost a little in size and weight, it has preserved its moderate gait and has continued to hunt near its master, “under the gun,” as they say. The same is the case in Spain, Italy and Germany even. In France there are several varieties or sub-breeds of brach hounds. The old French brach, which is nothing more than the old type, preserved especially in the south, where it is called the Charles the Tenth brach, is about twenty-four inches in height, and has a white and a maroon coat, which is somewhat coarse. It often has a cleft nose and dew-claws on all the feet. The brach of the south scarcely differs from the preceding except in color. Its coat has a white ground covered with pale orange blotches and spots of the same color. The St. Germain brach is finer bred, and appears to be a pointer introduced into France in the time of Charles X. It has a very fine skin, very fine hair of a white and orange color. The Bourbon brach has the characters of the old French brach, with a white coat marked here and there with large brown blotches, and the white ground spotted with the same color; but what particularly characterizes this dog is that it is born with a stumpy tail, as if three-quarters of it had been chopped off. The Dupuy brach is slender and has a narrow muzzle, as if it had some harrier blood in its veins. It is white, with large dark maroon blotches. The Auvergne brach resembles the southern brach, but has a white and black coat spotted with black upon white. The pointer, or English brach (Fig. 3), descends from the old Spanish brach, but has been improved and rendered lighter and much swifter of foot by the introduction of the blood of the foxhound into its veins, according to the English cynegetic authors themselves. The old pointer was of a white and orange color, and was indistinguishable from our St. Germain. The pointer now fancied is white and maroon and has a stronger frame than the pointer of twenty years ago. The Italian brachs are heavy, with lighter varieties, usually white and orange color, more rarely roan, and provided with dew-claws, this being a sign of purity of breed according to Italian fanciers. The German brachs are of the type of the old brach, with a stiff white and maroon coat, the latter color being so extensively distributed in spots on the white as to make the coat very dark. [Illustration: FIG 3.–POINTER.] Spaniels.–The old type of spaniel has nearly disappeared, yet we still find a few families of it in France, especially in Picardy and perhaps in a few remote parts of Germany. The old spaniel was of the same build as the brach, and differed from it in that the head, while being short-haired, was provided with ears clothed with long, wavy hair. The same kind of hair also clothed the whole body up to the tail, where it constituted a beautiful tuft. The Picard spaniel is a little lighter than the old spaniel. It has large maroon blotches upon a white ground thickly spotted with maroon, with a touch of flame color on the cheeks, over the eyes, and on the legs. The Pont-Andemer spaniel is a Norman variety, with very curly hair, almost entirely maroon colored, the white parts thickly spotted with a little color as in the Picard variety, and a characteristic forelock on the top of the head. [Illustration: FIG 4.–ENGLISH SETTERS.] In England, the spaniel has given rise to several varieties. In the first place there are several sub-breeds of setters, viz.: The English setter, still called laverack, which has large black or orange-colored blotches on the head, the rest of the body being entirely white, with numerous spots of the same color as the markings on the head (Fig. 4); the Irish setter, which is entirely of a bright yellowish mahogany color; and the Gordon setter, which is entirely black, with orange color on the cheeks, under the throat, within and at the extremity of the limbs (Fig. 5). Next come the field spaniels, a group of terrier spaniels, which includes the Clumber spaniel, which is white and orange color; the Sussex spaniel, which is white and maroon; the black spaniel, which is wholly black; and the cocker, which is the smallest of all, and is entirely black, and white and maroon, or white and orange-colored, or tricolored. [Illustration: FIG 5.–GORDON SETTER.] Barbets and Griffons.–To this latter category belong the dogs, par excellence, for hunting in swamps. The barbets are entirely covered with long curly hair, like the poodles, which are directly derived from them. They are white or gray, with large black or brown blotches. The griffons differ from the poodles in their coarse and stiff hair, which never curls. They have large brown blotches upon a white ground, which is much spotted or mixed, as in the color of the hair called roan. There is an excellent white and orange-colored variety. The griffons, neglected for a long time on account of the infatuation that was and is still had for English hunting dogs, are being received again with that favor which they have never ceased to be the object of in Germany and in Italy (where they bear the name of spinone). Breeders of merit, such as Mr. Korthals, in Germany, and Mr. E. Boulet, in France, are endeavoring to bring them into prominence (Fig. 6). Finally, we reckon also among hunting dogs some very happy crosses between the spaniels and the barbets, which in England are called retrievers or water spaniels.–P. Megnin, in La Nature. [Illustration: FIG 6.–COARSE HAIRED GRIFFON.] * * * * * RESTOCKING THE SEINE WITH FISH. A few days ago, at Bougival, a short distance below the dam of the Marly machine, there were put into water 40,000 fry of California trout and salmon, designed to restock the Seine, which, in this region, has been depopulated by the explosions of dynamite which last winter effected the breaking up of the ice jam that formed at this place. [Illustration: RESTOCKING THE SEINE WITH FISH.] The operation, which is quite simple in itself, attracted a large number of inquisitive people by reason of the exceptional publicity given to the conflict provoked by a government engineer, who, under the pretext that he had not been consulted, made objections to the submersion of the little fish. As well known, the affair was terminated by a sharp reprimand from Mr. Yves Guyot, addressed to his overzealous subordinate. It would have been a great pity, moreover, if this interesting experiment had not taken place, and had not come to corroborate the favorable results already obtained. In three years the California salmon reaches a weight of eleven pounds, and, from this time, is capable of reproduction. Its flesh is delicious, and comparable to that of the trout, the development of which is less rapid, but just as sure. The fry put into the water on Sunday were but two months old. The trout were, on an average, one and a half inches in length, and the salmon two and three-quarter inches. They were transported in three iron plate vessels, weighing altogether, inclusive of the water, 770 lb., and provided with air tubes through which, during the voyage, the employes, by means of pumps, assured the respiration of the little fish. Our engraving represents the submersion at the moment at which the cylinders (of which the temperature has just been taken and compared with that of the Seine, in order to prevent too abrupt a transition for the fry) are being carefully let down into the river.–L’Illustration. * * * * * Figures show that the consumption of iron in general construction–other than railroads–in this country has grown from a little more than a million and a half of tons in 1879 to more than six million tons in 1889. Much of this increase has gone into iron buildings. By using huge iron frames and thin curtain walls for each story supported thereon, as is done in a building going up on lower Broadway, New York city, a good deal of space can be saved. * * * * * MODERN ARMOR. By F.R. BRAINARD, U.S.N. The building of a navy, which has been actively going on for the past few years, has drawn public attention to naval subjects, and recent important experiments with armor plates have attracted large attention, hence it may not be amiss to give a description of the manufacture and testing of armor. It would be interesting to wade through the history of armor, studying each little step in its development, but we shall simply take a hasty glance at the past, and then devote our attention to modern armor and its immediate future. Modern armor has arrived at its present state of development through a long series of experiments. These experiments have been conducted with great care and skill, and have been varied from time to time as the improvements in the manufacture of materials have developed, and as the physical laws connected with the subject have been better understood. There has been very little war experience to draw from, and hence about all that is now known has been acquired in peaceful experiments. The fundamental object to be obtained by the use of armor is to keep out the enemy’s shot, and thus protect from destruction the vulnerable things that may be behind it. The first serious effort to do this dates with the introduction of iron armor. With this form of armor we have had a small amount of war experience. The combat of the Monitor and Merrimac, in Hampton Roads, in May, 1862, not only marked an epoch in the development of models of fighting ships, but also marked one in the use of armor. The Monitor’s turret was composed of nine one-inch plates of wrought iron, bolted together. Plates built in this manner form what is known as laminated armor. (See Fig. 1.) The side armor of the hull was composed of four one-inch plates. The Merrimac’s casemate was composed of four one-inch plates or two two-inch plates backed by oak. The later monitors had laminated armor composed of one-inch plates. The foregoing, with the Albemarle and Tennessee rams under the Confederate flag, are about the sum of our practical experience in the use of armor. [Illustration: Fig. 1.] European nations took up the subject of armor and energetically conducted experiments which have cost large sums of money, but have given much valuable data. For a long time wrought iron was the only material used for armor, and the resisting power depending on the thickness; and the caliber and penetration of guns rapidly increasing, it was not long before a point was reached where the requisite thickness made the load of armor so great that it was impracticable for a ship to carry it. The question then arose as to what were the most important parts of a ship to protect. The attempted solutions of this question brought out various systems of distributions. Armored ships were formerly of two classes; in one the guns were mounted in broadside, in the other in turrets. Every part of the ship was protected with iron to a greater or less thickness. In more modern ships the guns are mounted in an armored citadel, in armored barbettes or turrets, the engines, boilers and waterline being the only other parts protected. There may be said to be three systems of armor distribution. The belt system consists in protecting the whole waterline by an armored belt, the armor being thickest abreast of the engines and boilers. The guns are protected by breastworks, turrets or barbettes, the other parts of the ship being unprotected. The French use the belt system, and our own monitors may be classed under it. The central citadel system consists in armoring that part of the waterline which is abreast of the engines and boilers. Forward and aft the waterline is unprotected, but a protective deck extends from the citadel in each direction, preventing the projectiles from entering the compartments below. The hull is divided into numerous compartments by water-tight bulkheads, and, having a reserve of flotation, the stability of the ship is not lost, even though the parts above the protective deck, forward and aft, be destroyed or filled with water. The guns are protected by turrets or barbettes. The deflective system consists in inclining the armor, or in so placing it that it will be difficult or impossible to make a projectile strike normal to the face of the plate. A plate that is inclined to the path of a projectile will, of course, offer greater resistance to penetration than one which is perpendicular; hence, when there is no other condition to outweigh this one, the armor is placed in such a manner as to be at the smallest possible angle with the probable path of the projectile. This system is designed to cause the projectile to glance or deflect on impact. Deflective armor should be at such an angle that the projectiles fired at it cannot bite, and hence the angle will vary according to the projectile most likely to be used. In the usual form of deflective deck the armor is at such a small inclination with the horizon that it becomes very effective. Turret and barbette armor may be considered as deflective armor. The term inclined armor denotes deflective armor that is inclined to the vertical. The kinds of armor that are in use may be designated as rolled iron, chilled cast iron, compound, forged and tempered steel, and nickel steel. Iron armor consists of wrought iron plates, rolled or forged, and of cast iron or chilled cast iron, as in the Gruson armor. Compound armor consists of a forged combination of a steel plate and an iron plate. Steel armor consists of wrought steel plates. Nickel-steel armor consists of plates made from an alloy of nickel and steel. I have spoken above of laminated armor. To secure the full benefit of this kind, the plates must be neatly fitted to each other; the surfaces must make close contact. This requires accurate machining, and hence is expensive. To overcome this point sandwiched armor was suggested. This consists in placing a layer of wood between the laminations, as shown in Fig. 2. It was found that laminated and sandwiched armor gave very much less resisting power than solid rolled plates of the same thickness. Wrought iron armor is made under the hammer or under the rolls, in the ordinary manner of making plates, and has been exhaustively studied and experimented with–more so than any other form of armor. [Illustration: Fig. 2.] Chilled cast iron armor is manufactured by Gruson, in Germany, and is used in sea coast defense forts of Europe. In 1867 several compound plates were made by Chas. Cammell & Co., of Sheffield, England, and were tested at Shoeburyness, in England, and at Tegel, in Russia. These plates were made by welding slabs of steel to iron; but the difficulties were so great that the idea was abandoned for the time. [Illustration: Fig. 3.] [Illustration: FIG. 4.] Compound armor, as now manufactured, is of two types: Wilson’s patent, a backing of rolled iron, faced with Bessemer steel; Ellis’ patent, a backing of rolled iron, faced with a plate of hard rolled steel, cemented with a layer of Bessemer steel. Both these kinds are manufactured in England and France in sizes up to fifty tons weight. The Wilson process is used at the works of Messrs. Cammell & Co., of Sheffield, England, and the Ellis process at the Atlas Works of Sir John Brown & Co., of the same place. These are the two leading manufacturers of compound plate. [Illustration: Fig. 5.] The method employed by Wilson in making compound plate is to first make a good wrought iron plate. To the surface of this and along each side of the length of the plate are fixed two small channel irons, as shown in Fig. 5. The plate is then raised to a welding heat in a gas furnace, and transferred to an iron flask or mould. Wedges are driven in between the back of the plate and the side of the mould, thus forcing the channel irons up snug against the opposite side of the mould. Moulding sand is then packed around the back and sides of the plate (see Fig. 6). The mould is lowered in a vertical position into a pit. Molten steel, manufactured by either the Siemens-Martin or Bessemer process, is then poured in through a trough that forms several streams, and forms the hard face of the plate. The molten steel as it runs down cleans the face of the wrought iron plate, scoring it in places, and, being of much higher temperature, the excessive heat carbonates the iron to a depth of one-eighth to three-sixteenths of an inch, forming a zone of mild steel between the hard steel and soft iron. The mould is placed in a vertical position to insure closeness of structure and the forcing of gases out of the steel. After solidifying, the whole plate is pressed, and passed through the rolls to obtain thorough welding. It is then bent, planed, fitted, tempered, and annealed to remove internal strains. [Illustration: Fig. 6.] In 1887, Wilson took out a patent for improvements in his process of making compound plates. In this method of manufacture he takes a wrought iron, fibrous plate, fifteen inches thick, built up from a number of thin plates. While hot from the forging press, he places this plate in an iron mould (see Fig. 7) about 28 inches deep, and upon it runs “ingot iron” or very mild steel to a depth of thirteen inches. In this form of mould the plate rests on brickwork, and is held in place by two grooved side clamps or strips which are caused to grip the plate by means of screws which extend through the sides of the mould. After solidifying, the plate, which is twenty-eight inches thick, is reheated and rolled down to eighteen inches. This is the iron backing of the finished plate, and it is again put in the iron mould and heated, when a layer of hard steel is run on the exposed surface of the original wrought iron plate to a depth of eight inches. This makes a plate about twenty-eight inches thick. It is taken from the mould, reheated, rolled, hammered or pressed down to twenty inches. After cooling, it is bent, planed, and fitted as desired, then tempered and annealed to relieve internal strains. [Illustration: Fig. 7.] The method employed by Ellis in making compound plates is to take two separate plates, one of good wrought iron and one of hard forged steel, placing the forged steel plate on the wrought iron plate, keeping them separate by a wedge frame or berm of steel around three sides, and placing small blocks of steel at various points near the middle of the plates (see Fig. 8). These blocks are called distance blocks. After covering all the exposed steel surfaces with ganister, the plates are put in a gas furnace and heated to a welding heat. They are then lowered into a vertical iron pit with the open side uppermost. The plates are held in position by hydraulic rams, which also prevent bulging. Molten steel of medium softness is then poured into the space between the plates, by means of a distributing trough having holes in the bottom, and after this has solidified, the whole plate is placed under the hydraulic press and reduced about twenty per cent. in thickness. The plate is then passed through the rolls, bent, planed, fitted, tempered, and annealed to reduce internal strains. [Illustration: Fig. 8.] In heating the compound plates for rolling, the plate is placed in the furnace with the steel face down, so that the iron part gets well heated and the steel does not become too hot. Great care must be taken not to overheat the plate, and in working, many passes are given the plate with small closings of the rolls. The steel part of a compound plate is usually about one third of the full thickness of the plate. Forged steel armor, tempered in oil, is fabricated at Le Creusot, France, by Schneider & Co., using open-hearth steel, and forging under the 100 ton hammer. The ingots are cast, with twenty-five per cent. sinking head and are cubical in form. The porter bar is attached to a lug on one side of the ingot. By means of a crane with a curved jib which gives springiness under the hammer, the ingot is thrust into the heating furnace. On arriving at a good forging heat it is swung around to the 100 ton hammer, under which it is worked down to the required shape. A seventy-five ton ingot requires about eight reheatings before being reduced to shape. Having been reduced to shape, the plate is carefully annealed, then raised to a high tempering heat, and the face tempered in oil. It is reannealed to take out the internal strains, care being taken not to reduce the face hardness more than necessary. The Schneider process of tempering is based upon the utilization of the absorption of heat caused by the fusing or melting of a solid substance, and of the fact that so long as a solid is melting or dissolving in a liquid substance, the liquid cannot get appreciably hotter, except locally around the heating surface. The body to be hardened is plunged at the requisite temperature into a bath containing the solid melting body, or is kept under pressure in the solid material of low melting point until the required extraction of heat has taken place, more solid material being added if necessary as that originally present melts and dissolves. Nickel steel armor is made in a similar manner to the steel plates, the material used in casting the ingot being an alloy of nickel and steel containing between three and four per cent. of nickel. The Harvey process of making armor consists in taking an all-steel plate and carbonizing the face. This carbonizing process is very similar to the cementation process of producing steel, and by it the face of the plate is made high in carbon and very hard. The system invented by Sir Joseph Whitworth, of Manchester, England, consists in what might be called scale armor. A section of a sample of the armor represents four plates. The outer layer, one inch thick, is composed of steel of a tensile strength of 80 tons per square inch; the second layer, one inch thick, of steel whose tensile strength is 40 tons per square inch; the third and fourth layers, each one-half inch thickness, of mild steel. The outer layer is in small squares of about ten inches on a side, and is fastened to the second layer by bolts at the corners and one in the middle of each square. The surface is flush. (See Fig. 9.) The end sought by the above system is to break up the shot by the hard steel face and to restrict any starring or cracking of the metal to the limit of the squares or scales struck. The bolts are of high carbon and are extremely hard steel. [Illustration: Fig. 9.] Armor plates must often be bent or curved to single or double curvature and sometimes to a warped surface to fit the form of the ship. There are several methods of bending plates. One method employs a cast iron slab of the required form, which is placed on the piston of a hydraulic press. The armor plate is placed face down on this slab, and on top of the plate are laid packing blocks of cast iron, of such sizes and shapes as to conform to the required curve. These blocks take against the upper table of the press, when the piston is forced up, and the hot plate is thus dished to the proper form. In the French method of bending, an anvil or bed plate of the required curve is used, and the armor plate is forced to take the curve by being hammered all over its upper surface with a specially designed steam hammer. The edges of the plate are trimmed by large, powerful slotting machines or circular saws; the latter, however, operate in exactly the same manner as a slotter, except that there is no return motion to the tool. Each tooth of the saw is but a slotting tool, and these teeth are, by screws, rendered capable of being nicely adjusted in the circumference of the saw. The plates are fastened to the hulls and backing by heavy bolts, varying in size according to the weight of the individual plate. For the 6,000 ton armored ships, these bolts are from 2.75 to 3.1 inches in diameter and from 18.45 to 23 inches in length. They are tapped two or three inches into the armor and do not go through the plate. They pass through wrought iron tubes in the backing and set up with cups, washers and nuts against the inner skin of the ship. At steel works where plates for our new navy are being manufactured, there are inspectors who look after the government’s interests. Officers of the navy are detailed for this work, and their duty is to watch the manufacture of plates through each part of the process and to see that the conditions of the specifications and contract are complied with. The inspection and testing of armor plates consists in examining them for pits, scales, laminations, forging cracks, etc., in determining the chemical analysis of specimens taken from different parts, in determining the physical qualities of specimens taken longitudinally and transversely, and the ballistic test. Specifications for these different tests are constantly undergoing change, and it would be impossible to state, with exactness, what the requirements are or will be in the near future. The ballistic test is the important one, and is made by taking one plate of a group and subjecting it to the fire of a suitable gun. The other tests are simply to insure, as far as practicable, that all the other plates of the group are similar to and are capable of standing as severe a ballistic test as the test plate. The following will give an idea of the ballistic test as prescribed by the Bureau of Ordnance, Navy Department. The test plate, irrespective of its thickness, is to be backed by thirty-six inches of oak or other substantial wood. Near the middle region of the plate an equilateral triangle will be marked, each side of which will be three and one-half calibers long. The lower side of the triangle will be horizontal. Three shots will be fired, the points of impact being as near as possible the extremities of the triangle. The velocity of the shot will be such as to give the projectile sufficient energy to just pass through a wrought iron plate of equal thickness to the test plate, and through its wood backing. The velocity is calculated by the Gavre formula: a V squared = — { 3507 E squared x 2265464 e^{1.4} } w [TEX: V^2 = \frac{a}{w} { 3507 \ E^2 \times 2265464 \ e^{1.4} }] V = the velocity of the projectile in feet per second. a = the diameter of the projectile in inches. w = the weight of the projectile in pounds. E = the thickness of the backing in inches. e = the thickness of the plate in inches. Using the above formula we can make out a table as follows: ——-+——-+————-+——-+——-+——+———+ Plate. |Backi’g| Gun, service| w, | a, | V. | Energy, | Inches.|Inches.| shot. |Pounds.|Inches.| f. 8.| Impact. | | | | | | | f. tons.| ——-+——-+————-+——-+——-+——+———+ 6 | 36 | 6″ B.L.R. | 100 | 5.96 | 1389 | 1337 | 7 | 36 | 6″ ” | 100 | 5.96 | 1528 | 1619 | 8 | 36 | 8″ ” | 250 | 7.96 | 1213 | 2550 | 9 | 36 | 8″ ” | 250 | 7.96 | 1308 | 2966 | 10 | 36 | 8″ ” | 250 | 7.96 | 1399 | 3390 | 11 | 36 | 8″ ” | 250 | 7.96 | 1489 | 3839 | 12 | 36 | 10″ ” | 500 | 9.96 | 1247 | 5386 | 13 | 36 | 10″ ” | 500 | 9.96 | 1315 | 5987 | 14 | 36 | 10″ ” | 500 | 9.96 | 1381 | 6608 | 15 | 36 | 12″ ” | 850 | 11.96 | 1215 | 8699 | 16 | 36 | 12″ ” | 850 | 11.96 | 1269 | 9710 | 17 | 36 | 12″ ” | 850 | 11.96 | 1332 | 10454 | 18 | 36 | 12″ ” | 850 | 11.96 | 1374 | 11124 | 19 | 36 | 12″ ” | 850 | 11.96 | 1425 | 11965 | 20 | 36 | 12″ ” | 850 | 11.96 | 1476 | 12837 | ——-+——-+————-+——-+——-+——+———+ No projectile or fragment of the plate or projectile must get wholly through the plate and backing. The plate must not break up or give such cracks as to expose the backing, previous to the third shot. The penetration of projectiles of different forms into various styles of armor has been very thoroughly studied and many attempts have been made to bring the subject down to mathematical formulae. These formulae are based on several suppositions, and agree very closely with results obtained in actual experiments, but there are so many varying conditions that it is extremely doubtful if any formulae will ever be written that will properly express the penetration. Many different forms have been given to the heads of projectiles, as flat, ogival, hemispherical, conoidal, parabolic, blunt trifaced, etc. The flat headed projectile has the shape of a right cylinder, and acts like a punch, driving the material of the armor plate in front of it. These projectiles are especially valuable when firing at oblique armor, for they will bite or cut into the armor when striking at an angle of thirty degrees. The ogival head acts more as a wedge, pushing the metal aside, and generally will give more penetration in thick solid plates than the flat headed projectile. The ogival head is usually designed by using a radius of two calibers. The hemispherical, conoidal, parabolic and blunt trifaced all give more or less of the wedging effect. The blunt trifaced has all the good qualities of the ogival of two calibers. It bites at a slightly less angle, and the three faces start cracks radiating from the point of impact. Forged steel is the best material for armor-piercing projectiles, but many are made of chilled cast iron, on account of its great hardness and cheapness. The best weight for a projectile is found by the formula w = d cubed (0.45 to 0.5) w being the weight in pounds, d the diameter in inches and 0.45 to 0.5 having been determined by experiment. With a light projectile we get a flat trajectory, and accuracy at short ranges is increased. With a heavy projectile the resistance of the air has less effect and the projectile is advantageously employed at long ranges. In the following formulae, used in calculating the penetration of projectiles in rolled iron armor, g = the force of gravity. w = the weight of projectile in pounds. d = the diameter of projectile in inches. v = the striking velocity in feet per second. P = the penetration in inches. Major Noble, R.A., gives _________________ 1.6 / w v squared P = /\ / —————- / [pi] g d 11334.4 [TEX: P = \sqrt[1.6]{\frac{w \ v^2}{\pi \ g \ d \ 11334.4}}] U.S. Naval Ordnance Proving Ground uses ________________ 2.035/ w v squared P = /\ / ————— / [pi] g d 3852.8 [TEX: P = \sqrt[2.035]{\frac{w \ v^2}{\pi \ g \ d \ 3852.8}}] Col. Maitland gives w v squared P = ———— g d squared 16654.4 [TEX: P = \frac{w \ v^2}{g \ d^2 \ 16654.4}] Maitland’s latest formula, now used in England, is _ v /w P = —– / – – 0.14 d 608.3 d [TEX: P = \frac{v}{608.3} \sqrt{\frac{w}{d}} – 0.14 \ d] General Froloff, Russian army, gives w v P = —— d squared 576 [TEX: P = \frac{w \ v}{d^2 \ 576}] for plates less than two and one-half inches thick, and w v P = —— – 1.5 d squared 400 [TEX: P = \frac{w \ v}{d^2 \ 400} – 1.5] for plates more than two and one-half inches thick. If [theta] be the angle between the path of the projectile and the face of the plate, then v in the above formulae becomes v sin [theta]. When we come to back the plates, their power to resist penetration becomes greater, and our formula changes. The Gavre formula, given above, is used to determine the velocity necessary for a projectile to pass entirely through an iron plate and its wood backing. Compound and steel armor are said to give about 29 per cent. more resisting power than wrought iron, but in one experiment at the proving ground, at Annapolis, a compound plate gave over 50 per cent. more resisting power than wrought iron. The Italian government, after most expensive and elaborate comparative tests, has decided in favor of the Creusot or Schneider all-steel plates, and has established a plant for their manufacture at Terni, near Rome. The French use both steel and compound plates; the Russians, compound; the Germans, compound; the Swedes and Danes use both. Spain has adopted and accepted the Creusot plate for its new formidable armored vessel, the Pelayo; and China too has recently become a purchaser of Creusot plates. Certain general rules may be laid down for attacking armor. If the armor is iron, it is useless to attack with projectiles having less than 1,000 feet striking velocity for each caliber in thickness of plate. It is unadvisable to fire steel or chilled iron filled shells at thick armor, unless a normal hit can be made. When perforation is to be attempted, steel-forged armor-piercing shells, unfilled, should be used. They may be filled if the guns are of great power as compared to the armor. Steel and compound armor are not likely to be pierced by a single blow, but continued hammering may break up the plate, and that with comparatively low-powered guns. Wrought iron must be perforated, and hard armor, compound or steel, must be broken up. Against wrought iron plates the projectile may be made of chilled cast iron, but hard armor exacts for its penetration or destruction the use of steel, forged and tempered. Against unarmored ships, and against unarmored portions of ironclads, the value of rapid-firing guns, especially those of large caliber, can hardly be overestimated. The relative value of steel and compound armor is much debated, and at present the rivalry is great, but the weight of evidence and opinion seems to favor the all-steel plate. The hard face of a compound plate is supposed to break up the projectile, that is, make the projectile expend its energy on itself rather than upon the plate, and the backing of wrought iron is, by its greater ductility, to prevent the destruction of the plate. It seems probable that these two systems will approach each other as the development goes on. An alloy of nickel and steel is now attracting attention and bids fair to give very good results. The problem to be solved, as far as naval armor is concerned, is to get the greatest amount of protection with the least possible weight and volume, and this reduction of weight and volume must be accomplished, in the main, by reducing the thickness of the plates by increasing the resisting power of the material. In the compound plate great surface hardness is readily and safely attained, but it has not yet been definitely determined what the proper proportionate thickness of iron and steel is. A considerable thickness of steel is necessary to aid, by its stiffness, in preventing the very ductile iron from giving back to such an extent as to distort the steel face and thus tear or separate the parts of the plate. The ductile iron gives a very low resisting power, its duty being to hold the steel face up to its work. If now we substitute a soft steel plate in the place of the ductile iron, we will get greater resisting power, but our compound plate then becomes virtually an all-steel one, only differing in process of manufacture. The greatest faults of the compound plate are the imperfect welding of the parts and the lack of solidity of the iron. When fired at, the surface has a tendency to chip. In the all-steel plate we have the greatest resisting power throughout, but there are manufacturing difficulties, and surface hardness equal to that of the compound plate has not been obtained. The manufacturing difficulties are being gradually overcome, and artillerists are in high hopes that the requisite surface hardness will soon be obtained. The following may be stated as well proved:

1. That steel armor promises to replace both iron and compound.
2. That projectiles designed for the piercing of hard armor must be made of steel.
3. That the larger the plate, the better it is able to absorb the energy of impact without injury to itself.