Chapter XX: Part XII: Artillery Carriages and Machines

1. What is meant by artillery carriages?

Carriages of every description employed in the artillery service.

2. How are such carriages classified?

Into two general divisions; first, those carriages on which artillery are mounted, either for firing or travelling; and secondly, such as are especially used for the transportation of artillery ammunition and stores.

3. What is a gun-carriage?

It is the machine on which a piece is mounted for manœuvering and firing.

4. Into what classes may gun-carriages be divided?

Into _movable_ and _stationary_ carriages.

5. What is the use of _movable_ carriages?

They are used for the transportation of the pieces as well as for firing them, and are mounted on large wheels. They are furnished with limbers.

6. Describe the _movable_ carriage.

It consists of two cheeks, connected together and with a stock by assembling bolts. The front part supports the piece, and rests upon an axle-tree furnished with wheels, the rear end of the stock or trail resting on the ground.

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7. What are the _cheeks_?

The parts of the carriage between which the piece is placed, and upon which the trunnions are supported.

8. What is the wheel composed of?

Of a nave into which the axle-tree enters; of a certain number of spokes fastened in the nave; and a circumference which is composed of a number of fellies equal to half the number of spokes.

9. What is the _dish_ of a wheel?

The inclination outward of the spokes, when fastened in the nave.

10. What is the advantage of this obliquity of the spokes?

It gives elasticity to the wheel, and protects it from the effect of shocks, which would destroy it, if the spokes were in the same plane.

11. What is the object of giving dish to a wheel?

For the purpose of making the body of the carriage wider; to diminish the length of the axle-tree, thus increasing its strength; to throw the mud and water outside the wheels; and to keep the wheel close against the carriage, and prevent any tendency to run off the axle.

12. How are movable gun-carriages distinguished?

As field, mountain, and siege-carriages.

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13. What are the principal considerations to be kept in view in the construction of movable carriages?

In firing, the carriage should yield to the recoil. Were it fixed immovably, it would soon be destroyed, no matter how great its solidity. Its weight should be proportional to that of the piece. If too heavy it would soon be destroyed by the shocks of the piece. If too light, the recoil would be immoderate. Its weight should always be less than that of the piece. A heavy piece upon too light a carriage will perform better service than the reverse arrangement, since the effort exerted by a piece depends upon its mass multiplied into the square of the velocity.

14. What are the principal considerations to be kept in view in the construction of field carriages?

Lightness and strength combined, great mobility and flexibility, and a low centre of gravity, in order to surmount all difficulties in the field which must frequently arise while artillery is acting with other troops,—to resist the concussion in firing, and the severe jolting produced when moving rapidly over uneven ground.

15. How many kinds of field gun-carriages have we?

Three, viz: One for the 6 pdr. gun and 12-pdr. howitzer; another for the 24-pdr. howitzer; and the third for the 12-pdr. gun and 32-pdr. howitzer.

16. In what respect are these carriages similar?

In all having the same kind of limber and the same-sized wheels, so that any limber or wheel may be used with any carriage; though, if possible, the heaviest wheel (No. 2) should be used on the carriage of the three heaviest pieces, 12-pdr. gun and 24 and 32-pdr. howitzers.

17. Describe these gun-carriages.

They consist of two short cheeks of wood, bolted upon a stock and wooden axle-body, in a recess of which fits the iron axle on which the wheels are placed. The stock terminates in a _trail_ and _trail-plate_ which rests on the ground, and has on the end a strong ring called the _lunette_, which is placed on the pintle hook when the piece is limbered. In the stock is placed an elevating screw-box of bronze in which the elevating screw fits.

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18. Mention other parts of a field-carriage.

Cap-squares, ear-plates, trunnion-plates, under-strap, elevating screw, wheel guard plate, axle-tree, trail-plate, trail-handles, prolong-hooks, pointing-rings, washer-hooks, lock-chain, sponge-chain, sponge and rammer stop, bolts, rings, bands, hooks, keys, straps, nuts, and nails.

19. What is the limber?

It consists of a similar axle-body, axle, and two wheels, and on these rests a frame-work to receive the tongue. On top of the whole is an ammunition box, the top of which forms a seat for three cannoneers. In rear of the axle-tree is a _pintle-hook_ to receive the lunette of the trail. Connected with the frame-work in front, is a fixed _splinter-bar_ with four hooks, to which are attached the traces of the wheel-horses. At the extremity of the tongue are placed two pole-chains, by which the tongue or pole is held up, and a pole-yoke with two movable branches, to prevent, as much as possible, the pole from oscillating and striking the horses.

20. What is the use of the limber?

To facilitate the movements of the carriage. By means of it a considerable portion of ammunition and stores may be conveyed for the immediate use of the piece, some of the cannoneers may be seated on the boxes, and by the simple manner in which it is attached to the carriage, the greatest facility is afforded for coming into action, or in retiring.

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21. Are there any other advantages from the manner in which the gun-carriage and limber are connected?

These two parts thus possess all the advantages of a four-wheel carriage, and the _freedom_ of motion peculiar to each admits of their passing over ground uninjured, or without being overturned or strained, where any other four-wheel carriage would invariably fail.

22. Describe the _mountain artillery_ gun-carriage.

It is formed like the field-gun carriage, but much smaller, the cheeks not being formed of pieces distinct from the stock, but all three made of two pieces bolted together. The axle-tree is of wood, which lessens the recoil, and gives an elasticity to the whole carriage, better adapted to resist the shocks of firing. The wheels are but thirty-eight inches high. Ordinarily, over rough ground, the carriage is transported on the backs of mules; but where it is possible, a pair of shafts is attached to the trail to keep it from the ground, and the piece is drawn on its carriage by harnessing one of the pack mules to it. The ammunition is carried in ammunition boxes on the backs of mules.

23. Describe the _prairie carriage_.

The necessity for a small carriage for the mountain howitzer when used on our western prairies, has led to the adoption of a special carriage for that service, with a limber attached as in a field-carriage. This renders the carriage less liable to overturn, and preferable in every respect to the two-wheeled one. The limber is furnished with two ammunition boxes, placed over the axle-tree, and parallel to it, and just wide enough for one row of shells and their cartridges.

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24. How many kinds of _siege-gun_ carriages are used in our service?

Three; one for the 12-pound gun; another for the 18-pdr.; and the third for the 24-pound gun and 8-in. howitzer.

25. In what respect are they similar?

They are all constructed in the same manner, differing only in their dimensions. All the limbers and wheels are the same, so that they can be used in common.

26. Describe this gun-carriage.

It is similar in its construction to the field-carriage, but is joined to the limber in a different way. Projecting upwards from the limber and in rear of the axle-tree, is placed a pintle, which enters a hole made in the trail from the underside, and a lashing-chain and hook keep the two parts together when once in position. The weight of the trail resting on the rear end of the tongue keeps this nearly horizontal, and relieves the horses of the weight of it, which, as it must be both long and heavy, is too much for the horses to carry.

The splinter-bar is, as in field carriages, stationary, but the traces of the next team are attached to a movable bar which is connected with the end of the tongue. The tongue is furnished with pole-chains, but no yoke, and the rest of the teams are harnessed as in field-artillery. The axle-trees are of iron, with axle-bodies of wood; which last, by its elasticity, renders the shock from the piece less direct and violent.

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On the upper surface of the cheeks, near the rear ends, are placed two projecting bolts which, with the curve of the cheeks, form resting places for the trunnions, when the piece is in position for transportation. They are called _traveling trunnion-beds_. When the piece is in this position, its breech rests upon the bolster, which is a curved block of wood, bolted to the upper side of the stock. On each side of the trail, and perpendicular to it, a strong manœuvring bolt is placed to serve as places to apply the handspikes in manœuvering the carriage.

27. What is the object of the traveling trunnion-beds?

For the purpose of distributing the load more equally over the carriage.

28. Mention the parts composing the limber.

The fork, the splinter-bar, the hounds, the sweep-bar, the tongue, the pintle, the lashing-chain, the axle-tree (iron). The sweep-bar is of iron, and on it rests the trail, which by its weight keeps up the tongue.

29. Why is it unnecessary for siege-carriages to have the same degree of mobility and flexibility as field carriages?

Because siege-carriages are, properly speaking, transportation wagons for use on roads, and never intended for manœuvring with troops.

30. How many horses does the transportation of siege-guns require?

A 24-pdr. requires ten horses (five drivers); a 12 or 18-pdr., eight horses (four drivers).

31. What are stationary gun-carriages used for?

To fire the piece from, and not to transport it except for short distances.

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32. For what service are these carriages used?

For garrison and sea-coast pieces; although the siege-gun carriages just described may also be used in a fortification or garrison. Mortar-beds, to be described hereafter, are used either for siege or garrison service.

33. What are the chief requisites for garrison and sea-coast carriages?

Strength, durability, and facility in serving the guns, as they are intended only for the works of a place, coast-batteries, and situations where they are permanently fixed.

34. Why should these carriages be required to possess great strength and durability?

Unless made strong they would soon be shaken by the continued and rapid fire which the defense of a work may demand; and from their constant exposure to the weather they would soon decay if made of a very perishable material.

35. Is the weight of garrison carriages a matter of great importance?

It is of less importance in this class of carriages than in any other, as they are seldom removed from their situations: their weight adds but little to the labor of running them up.

36. Mention the different _stationary_ carriages.

The carriage from which a mortar is fired, called its _bed_; the barbette-carriage; the columbiad-carriage; the casemate-carriage; and that for the 24-pdr. iron howitzer, called the flank-casemate carriage.

37. How many kinds of _siege mortar_ beds have we?

Four; the 8-in., 10-in., the stone, the coehorn.

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38. Which of these are alike?

The first three, differing only in dimensions. They are made of cast-iron, which has very little elasticity.

39. Describe these beds.

They consist of two cheeks, joined by two transoms, all cast together in the same piece. The manœuvring bolts, placed on each side, one near each end of the cheeks, are made of wrought iron, and set in the mould when the bed is cast.

On the front transom is fastened a wooden _bolster_, grooved to receive the elevating quoin. Notches, on the underside of the front and rear of the cheeks, give hold to the handspikes in throwing the carriage to the right or left.

40. Describe the _coehorn_ mortar-bed.

It is made of a block of oak wood, in one piece, or two pieces joined together with bolts. A recess, for the trunnions and part of the breech is made in the top of the bed; and the trunnions are kept in their places by plates of iron bolted down over them. Two iron handles are bolted to the bed on each side, by which four men can carry the bed with the mortar in its place.

41. Describe the _eprouvette_ mortar-bed.

It consists of a block of wood, on the top of which is countersunk and bolted the bed-plate, which is a heavy circular plate of cast-iron having a rectangular recess with sloping sides, so as to make it longest at the bottom. Into this recess the sole of the mortar slides. The wooden block is bolted to a stone block of the same size, which is firmly placed in the ground on a masonry foundation.

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42. Describe the _heavy sea-coast_ mortar bed.

The bed for the heavy ten-inch mortar is the only one which has yet been adopted. The cheeks are of cast-iron, and somewhat similar in form to those in the beds of siege-mortars; but in the front, the cheeks turn up to receive between them the front transom, which has, countersunk in and bolted to it, an elevating screw-bed, through which works an inclined elevating screw, which rises or falls by turning the nut, fitted on it by means of a lever inserted into mortises cut in the direction of the radii of the circular nut.

Both the transoms are made of wood, connected with the cheeks by mortises and tenons, and secured by bolts running through, and nuts on the outside. One of these bolts at each end, is longer than the others, and the projecting ends are made use of as manœuvring bolts. Directly behind and underneath the position for the trunnions, a bronze bed-piece is placed to receive the shock of the piece. It consists of a large beam of bronze, with each end well let in to the face of the cheek. The use of the elevating screw instead of the quoin, is rendered necessary by the great mass of metal to be raised or lowered in sighting the piece.

43. What is a _barbette_ carriage?

It is a carriage belonging to the class denominated immovable, on which a gun is mounted to fire _over_ a parapet; and a barbette gun is any gun mounted on a barbette-carriage.

44. How many forms of the barbette-carriage are in use in the service?

Two: one for _iron guns_ and sea-coast howitzers (12, 18, 24, 32, 42-pdrs., and 8 and 10-in.); and one for the columbiads.

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45. Of how many parts are barbette-carriages composed?

Of a _gun-carriage_ and a _chassis_.

46. Describe the gun-carriage.

It is formed of two upright pieces of timber, nearly vertical, behind which are placed two inclined braces, mortised into the uprights, and designed to receive the force of the recoil, the whole forming the cheeks, which are firmly connected and braced by transoms and assembling bolts, thus forming a _triangular_ frame-work, _which_ is less liable than any other form to become deformed from the shocks of the gun. A horizontal piece (the transom and axle-tie) runs from front to rear between the cheeks, connecting the axle-body and rear transom. The trunnion-bed is at the top of the upright, where it is joined to the brace; and the breech of the gun is supported on an elevating screw, working into a screw-box placed in the rear end of the transom and axle-tie. The front transom is just under the gun; the middle transom is between the braces; and the rear transom is at the lower end of the braces, and under the transom and axle-tie, into which it is notched; the lower part of this transom is notched to receive the tongue of the chassis on which it slides. Between this transom and the transom and axle-tie, the end of a lunette is placed projecting to the rear, and fastened by a bolt for the purpose of attaching a limber to the carriage.

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The feet of the uprights and front end of the transom and axle-tie are joined to an axle-body, in which an iron axle is placed. On the ends of the axle are fitted cast-iron rollers, which rest on the rails of the chassis, and support the front of the carriage. On the outside of the roller is placed an octagonal projection, on which the cast-iron nave of the wheel fits, secured by a washer and linch-pin. The spokes of the wheels are wood, inclosed within heavy iron tires. Manœuvring bolts are inserted in front of the feet of the uprights, and in the carriages, for pieces heavier than a 24-pdr., in rear of these feet also. These bolts and the spokes of the wheels form the points of application for the handspikes, in manœuvering the piece. Manœuvering staples are placed in front of the feet of the braces, for the purpose of using handspikes to raise the rear of the carriage from the tongue of the chassis in running to and from battery.

47. What pieces go on the same carriage?

The 32-pound gun, and 8-inch howitzer. All other pieces have separate carriages.

48. How many sizes of rollers are used?

Two: one for the carriages of the 12, 18, and 24-pounders; the other for the remaining carriages.

49. Are cap-squares used with these carriages?

No.

50. What other purposes do the wheels subserve besides assisting in manœuvering the gun-carriage?

In transporting the piece on its carriage for short distances, as from one front of a fort to another.

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51. Describe the chassis.

It consists of two _rails_ and a _tongue_, joined by three transoms. The tongue is in the middle, and projects considerably beyond the rails, to the rear. At each end of the rails on top, a hard piece of wood is notched in, and bolted. They are called hurters and counter-hurters, and their use is to prevent the gun carriage from running off the chassis. Rail-plates of iron to protect the wooden rails are let in to the outside of the rails. At the rear end of the tongue, a swinging prop is placed to support the end of the tongue when the piece is run back. The lower side of the end of the tongue is notched out, and a manœuvering loop fixed there, with a bolt and screws, to assist in handling the chassis. On the under side of each rail, opposite the rear transom, a mortise is formed, for the reception of a socket of iron which receives the _handle_ of the traverse-wheel fork. Each of these forks receives a traverse-wheel, joined to it by an axle-bolt, and these support the rear end of the chassis. The front end is supported on a pintle-plate of iron; through which, and up into the middle of the front transom, passes a pintle or bolt, which serves as a pivot around which the whole system moves.

52. In permanent batteries, how are the pintle and traverse circle fixed?

The pintle is fixed in a block of stone, and the traverse circle is an iron plate set also in stone.

53. In temporary batteries, how is the pintle attached?

To a wooden bolster which is covered by a circular cast-iron plate, and attached by bolts to a wooden cross picketed firmly into the ground.

54. How may a temporary traverse circle be made?

Of plank, pinned to sleepers, and fastened to pickets, or secured to string-pieces, which connect the traverse circle with the pintle-cross.

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55. What retains the traverse-wheels and their forks in their places?

The weight of the carriage and gun, and the form of the socket and handle of the fork.

56. Where are the handspikes applied in traversing the carriage?

To the pivot-bolts of the traverse-wheels, which project to the rear; or under the traverse-wheels.

57. Why does the chassis slope towards the front?

In order to diminish the recoil, and aid in running the piece into battery.

58. Describe the _columbiad_ gun-carriage.

It is a triangular frame-work, consisting on each side of an upright, a horizontal rail or tie, and a brace, firmly mortised and bolted together, forming the cheeks, which are joined by a transom at each end. These project below the lower surfaces of the ties, and fit in between the rails of the chassis, serving, like the flanges on the rollers in the other barbette-carriages, to prevent the gun-carriage from slipping sideways off the chassis.

Through the front transom, and near the front ends of the ties, an iron axle-tree is passed, working in iron boxes fitting in the ties. On the projecting ends of this axle-tree the rollers or manœuvring wheels are fixed (the axes of which are _eccentric_ with the axis of the axle-tree) the extreme ends of the axle, being octagonal in shape, to fit the wrench of the iron handspike.

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These _eccentrics_ are so arranged that when the centres of the wheels are at their lowest points, the surfaces of the wheels bear on the rails of the chassis and raise the gun-carriage tie from it; and when the centres are at the highest points, the surfaces of the wheels do not touch the rails, and the ties are in contact with them.[2] A similar arrangement is made for the rear part of the carriage, except that the axle does not extend all the way through, but the wheel on each side has a projecting piece of axle which works into a box placed near the end of the tie.

[2] A couple of notches or indentations are made on the ends of the eccentric axles. When these notches are in a vertical line, the wheels rest on the _rails_; but when they are in a horizontal or inclined line, the ties rest on _them_.

The wheel is thrown into or out of gear, that is, made to bear on the rail of the chassis or relieved from it, by turning the axle with a wrench placed on the octagonal end. In the direction of the radii of the wheels, but inclined outwards, mortises are placed for the reception of the end of the iron handspikes, by acting on which while inserted the wheels are turned, and the carriage moved back and forth on the chassis. Ordinarily, when the wheels are thrown into gear, the carriage being back, it will run into battery of itself.

The elevating arrangement consist of an elevating screw, working into a screw-bed, which slides in a vertical box, and carries on the top of it a movable _pawl_ to fit into the notches cut in the breech of the gun, in order to give considerable elevations. For the purpose of transferring the pawl from one notch to the next, it has a slit in it, through which the elevating bar is passed, and the gun supported by making use of the edge of the elevating-box as a fulcrum. This arrangement is over the rear transom.

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59. Describe the chassis of the columbiad-carriage.

It consists, like those used with other barbette-carriages, of two rails connected by three transoms; but the tops of the rails are shod with iron plates, and the rear hurters are the large heads of heavy bolts which pass entirely through the rails. The front hurters are fixed to the front transom by a heavy plate and bolt.

Traverse-wheels are placed under both front and rear transoms, and the chassis moves on a pintle passing through the middle transom. Two of these wheels are placed under each end of the chassis, their axes being kept in place by straps bolted to the transoms. Recesses are cut in the underside of the transom, for the wheels to turn in. This chassis has no tongue.

60. Of how many parts are casemate carriages composed?

Like barbette-carriages, of a _gun-carriage_ and _chassis_.

61. Describe the gun-carriage.

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It consists of two cheeks, joined together by as many transoms, and supported in front by an axle-tree on truck wheels, and in rear on the rear transom, which is notched to fit the tongue of the chassis. Each cheek is formed of two pieces, one on top of the other, and connected by dowels and bolts. On the underside, near the front, a notch is cut for the reception of the axle-tree, which is of oak; and nearly over the axle, on the upper side of the cheek, the trunnion-bed is placed. The rear of the upper piece of the cheek is cut into steps, which give a better hold for the assembling-bolts, than a uniform slope, and give purchases for the handspikes, in elevating the piece. On the inside of each cheek, just in rear of the axle, a vertical guide is fixed to keep the carriage on the chassis. It is of wood, and bolted to the front transom and axle-tree. The top of the front transom is hollowed out, to admit the depression of the piece. Behind the rear transom and at the notch cut in it, there is an eccentric-roller, so arranged as to bear the weight of the rear part of the carriage, or not, according as it is thrown in or out of gear.

Near the rear end of each cheek, and outside, a heavy trail-handle of iron is placed, and used in manœuvring the piece. On the ends of the axle truck wheels are placed, with mortises sloping outwards in the direction of the radii, for the insertion of the handspikes in running from battery.

The elevating apparatus consists of a cast-iron bed-plate, secured to the rear transom; an elevating screw and brass nut; the nut being acted on by an oblique-toothed wheel, turned by a handle placed outside the right cheek.

62. Describe the chassis.

It consists of two rails and a tongue, joined by two transoms, and supported on traverse-wheels in front and rear. The track on each rail is curved up at each end, and provided with hurters to prevent the carriage from running off the chassis. A prop fastened under the rear end of the tongue prevents the chassis from upsetting backwards in firing heavy charges, and may be used as a point of support in raising the chassis. An iron fork is bolted to the under side of the front end of the tongue, to which is bolted an iron tongue. An opening in the masonry below the embrasure, is left for this tongue, and it is secured in its place by dropping the pintle from the embrasure down through the eye of the tongue.

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63. Where is the _flank-casemate_ carriage employed?

It is especially adapted to the mounting of the 24-pdr. iron howitzer in the flanks of casemate batteries, for defending the ditch; and both the gun-carriage and chassis are narrower and lighter than the other casemate carriages.

64. Describe the gun-carriage.

The cheeks are made of white oak, and connected by two iron transoms, the front one projecting below the cheeks, and resting on the chassis with a projection on the bottom of it, fitting in between the rails. The bottom of the trail has the same slope as the upper surface of the chassis on which it rests; so that when its eccentric-roller is out of gear, the rear parts of the cheeks fit the rails. The remaining portion of the bottom of the cheek makes an angle with the rail, and has in front a fork, and a roller which runs on the rail of the chassis when the eccentric is in gear. Each cheek has on the side a trail-handle and a manœuvring-ring. In rear of the rear transom is placed an eccentric-roller, having a projection in the middle of it, just large enough to fit in between the rails of the chassis, and guide the trail of the carriage. When this _roller_ is in gear, the weight of the trail rests upon _it_, while that of the front part of the carriage is thrown upon the front rollers, and the piece is then easily run in and out of battery; but the roller being out of gear, as when the piece is about to be fired, the weight rests upon the rear part of the cheeks and the front transom, and friction is brought into play to diminish the recoil. Cap-squares are used with this carriage.

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65. Describe the chassis.

It consists simply of two rails 3 in. apart, and joined by four transoms and assembling-bolts. Hurters on the rear ends of the rails only are used, as the bottom projection of the front transom prevents the carriage running too far into battery. The front end of the chassis rests on the sole of the embrasure. The end is provided with a pintle-plate and a strap of half-in. iron through which the pintle passes to the masonry beneath. The rear of the chassis is supported by an iron prop, the lower end of which is attached to two traverse-wheels.

66. What kind of carriages have been recommended for use in garrisons, instead of wooden ones?

Wrought iron carriages, for all except the flank-casemate; all made in a similar manner, differing only in weight and dimensions.

67. What is the objection to cast-iron?

Its weight, and its great liability to splinter when struck by shot.

68. Of how many parts is this wrought iron carriage composed?

Like the wooden ones, of a gun-carriage and chassis.

69. Describe the gun-carriage.

It consists of two cheeks of thick sheet-iron, each one of which is strengthened by three flanged iron plates bolted to the cheeks. Along the bottom of each cheek, an iron shoe is fixed with the end bent upwards.

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In front, this bent end is bolted to the flange of the front strengthening plate. In rear the bent portion is longer, and terminated at top by another bend, which serves as a point of application for a lever on a wheel, when running to and from battery. The trunnion-plates fit over the top ends of the strengthening plates, which meet around the bed, and are fastened to the flanges of the latter by movable bolts and nuts.

The _cheeks_ are joined together by transoms made of bar-iron. _They_ are parallel to each other, and in order that the _base ring_ on the gun may not interfere with giving it the full elevation by striking against them, it is proposed to dispense with the _base ring_ in sea-coast and garrison pieces, and to retain the preponderance by reducing the swell of the muzzle.

The front of the carriage is mounted on an axle-tree, with truck wheels similar to the wooden casemate carriages.

70. Describe the chassis.

It consists of two rails of wrought iron, the cross section of each being in form of a T, the flat surface on top being for the reception of the shoe-rail of the gun-carriage. The rails are parallel to each other, and connected by iron transoms and braces. The chassis is supported on traverse-wheels.

A prop is placed under the middle transom of the chassis, to provide against sagging.

71. What carriage is used for conveying ammunition for a field battery?

The CAISSON.

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72. Describe it.

A four-wheel carriage, consisting of two parts, one of which is a limber similar to that of the gun carriage, and connected in a similar way by a wooden stock and lunette.

On the axle-body of the rear part, and parallel to the stock, are placed three rails upon which are fastened two ammunition boxes, one behind the other, and similar to the one on the limber; so that the caisson has three ammunition boxes which will seat nine cannoneers. The interior compartments of the ammunition boxes vary according to the nature of the ammunition with which they are loaded. In rear of the last box is placed a spare wheel, axle of iron, with a chain and toggle at the end of it. On the rear end of the middle rail is placed a carriage hook, similar to a pintle-hook, to which the lunette of a gun carriage whose limber has become disabled, may be attached, and the gun carried off the field.

The caisson has the same turning capacity and mobility as the gun carriage, so that it can follow the piece in all its manœuvres, if necessary. It also carries a spare wheel, spare pole, &c.

73. What provision is made for repairing the carriages of a field battery when required?

Every field battery is provided with a FORGE.

74. Describe this wagon.

It consists, besides the limber, of a frame-work on which is fixed the bellows, fire-place, &c. Behind the bellows is placed a coal-box, which has to be removed before the bellows can be put in position. In the limber box are placed the smith’s tools, horse-shoes, nails, and spare parts (iron) of carriages, harness, &c.

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75. Describe the _battery wagon_.

It consists, besides the limber, of a long-bodied cart with a round top, which is connected with the limber in the same way as all other field carriages. The lid opens on hinges placed at the side; and in rear is fixed a movable forage rack for carrying long forage. One of these wagons accompanies each field-battery, for the purpose of transporting carriage-maker’s and saddler’s tools, spare parts of carriages, harness and equipments, and rough materials for replacing different parts.

Both this and the forge are made of equal mobility with the other field carriages, in order to accompany them wherever they may be required to go.

76. How many kinds of wheels are employed for field carriages?

Two: No. 1 for the 6-pdr. gun carriage, the caisson, the forge, the battery-wagon, and for the limbers of all field-carriages. No. 2 for the 24-pdr. howitzer and the 12-pdr. gun carriages.

77. In what respects are these wheels similar?

They are of the same form and height, and they fit on the same axle-tree arm. The height is 57 inches, and each wheel is composed of 14 spokes and 7 fellies.

78. How do they differ?

In the dimensions of their parts, and in strength and weight.

79. What is the weight of these wheels?

No. 1, 180 lbs., No. 2, 196 lbs.

80. What are the weight and height of a wheel of siege-gun carriages and limbers?

Weight 404 lbs., and height 60 inches.

81. What is the _portable forge_ designed for?

Service in a mountainous country, where wheeled vehicles cannot travel, for the purpose of making repairs, not only for the artillery but for all other arms of service taken on such expeditions.

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82. What is the _mortar wagon_ designed for?

The transportation of siege mortars and their beds, or of guns or large shot and shells.

83. Describe this wagon.

The limber and wheels are the same as those of the siege-gun carriage. The body consists of a platform of rails and transoms, resting on an axle-tree, the two middle rails being prolonged to form the stock; six stakes or standards are inserted in sockets on the side of this platform and used to secure the load.

The side-rails are prolonged to the rear, and furnish pivots for a roller placed immediately in rear of the platform. This roller has holes for the insertion of handspikes, and is used in loading the wagon; the guns, mortars, &c., being drawn up on the stock.

A muzzle bolster on the stock near the limber, and a breech-hurter near the hind part of the wagon, are provided and used when long ordnance is transported on it.

Mortars are usually carried mounted on their beds.

84. What is the use of the _hand-cart_?

For the transportation of light stores in siege and garrison service.

85. Describe it.

It consists of a light body with shafts, mounted on two wheels. The shafts are joined together at the ends, and supported immediately in front of the body by iron legs.

[Sidenote: 146]]

86. What is the use of the _hand sling-cart_?

It is used in siege and garrison service for transporting artillery short distances.

87. Describe it.

It is a two-wheeled carriage made entirely of iron, except the pole, which is of oak. The axle-tree is arched to make it stronger, and connected with the pole by strong wrought iron straps and braces. In the rear of the axle a projection is welded to receive the end of a strong hook. The end of the pole terminates in a ferule and an eye. The eye is for the purpose of attaching to the cart when necessary, a limber or a horse.

88. How great weights can be transported by this cart?

It should not be used with heavier weights than about 4000 lbs., but in case of necessity a 24 or 32-pd. gun may be transported on it. For heavier guns or material, the large _sling-cart_ drawn by horses or oxen should be used.

89. What is the _field and siege gin_ and its use?

It consists, like all gins, of two legs and a pry-pole, a windlass, sheaves, pulleys, and a fall or rope, and is used for mounting or handling guns, or other heavy bodies, in the field or in the trenches of a siege. The legs are about 14½ feet long and the height of the gun about 12 feet.

90. How does the _garrison gin_ differ from the field and siege gun?

It is heavier and stronger, as it is used for mounting heavier guns, and has not to be transported like the other with an army in the field. The legs are longer and the gin higher than the other.

91. Describe the _casemate gin_.

It does not differ from the garrison gin except in its height (which is about that of the field and siege gin) and the thickness and strength of the parts.

[Sidenote: 147]]