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 pupæ, 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 is not a native of this country, but was imported from Europe.
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 antennæ 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 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 pupæ, 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.
FIG. 26.
The moths, Fig. 26, d, belong to the family commonly known as plume moths or feather wings (Pterophoridæ), 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 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 thekjoekkenmoedding(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 geologistsCanis 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 themolossithat 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
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.
FIG.1--LARGE ST. BERNARD DOG BELONGING TO MR. LEONARD.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 café-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.
FIG. 2FIG. 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.
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 thebracco, whence doubtless is derived the French namebraqueand English brach. Finally theagasseof 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 rarelyroan, 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.
FIG 3.--POINTER.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.
FIG 4.--ENGLISH SETTERS.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.
FIG 5.--GORDON SETTER.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 ofspinone). 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.
FIG 6.--COARSE HAIRED GRIFFON.FIG 6.—COARSE HAIRED GRIFFON.
[1]
Les Races des Chiens, in La Bibliotheque de l'Eleveur.
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.
RESTOCKING THE SEINE WITH FISH.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.
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.)Fig. 1. LaminatedThe 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.
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.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.
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.
Fig. 3.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.
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.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).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.
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)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.
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).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.
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.)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.
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:
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: