THE
HAND-BOOK OF ARTILLERY,
FOR THE
SERVICE OF THE UNITED STATES,
(ARMY AND MILITIA.)
WITH THE
MANUAL OF HEAVY ARTILLERY, INCLUDING
THAT OF THE NEW IRON CARRIAGE.
BY
JOSEPH ROBERTS,
MAJOR 4TH REGT. ART., U. S. A., AND COLONEL 3D PENN. ART.
FIFTH EDITION,
REVISED AND GREATLY ENLARGED.
NEW YORK:
D. VAN NOSTRAND, 192 BROADWAY.
1863
ENTERED, according to Act of Congress, In the year 1863, by
JOSEPHROBERTS,
In the CIerk’s Office of the District Court of the United States for the
Southern District of New York.
JOHN P. TROW
Printed, stereotyped, and electrotyped.
46, 48, & 50 Greene Street,
New York..
The following compilation was prepared for the instruction of non-commissioned officers and privates of the Artillery School, where it was in successful use as a text-book. Much of the matter is taken from Burns’ Questions and Answers on Artillery, Gibbon’s Artillerist’s Manual, Heavy Artillery Tactics, the Ordnance Manual, and Kingsbury’s Artillery and Infantry.
The compiler acknowledges his indebtedness to a work on Ordnance and Gunnery, by Captain Benton, for a portion of the matter on Rifle Cannon.
FORT MONROE, VA., 1863.
_______________
PAGE
PREFACE TO FIFTH EDITION,
. . .
. . .
. . 4
GENERAL TABLE OF CONTENTS,
.
. . 6
PROCEEDINGS, . .
. . . . . .
. . . . . .
. . . 7
PART I. SECTION 1. ARTILLERY INGENERAL,
. . . . 9
”
“ 2. GUNS, . .
. . . .
. . . .
28
“
“ 3. HOWITZERS, .
. . . .
. . . 30
“
“ 4. COLUMBIADS, .
. . . .
. . . 32
“
“ 5. MORTARS,
. . . .
. . . . 33
“ “ 6. SEA-COAST ARTILLERY, . . . . 36
“ “ 7. SIEGE ARTILLERY, . . . . . . 39
“ “ 8. FIELD GUNS AND FIELD BATTERIES, 43
PART II. SECT. 1. POINTING GUNS AND HOWITZERS, 64
2.
POINTING MORTARS, . .
. . 60
PART III. CHARGES,
.
. . .
. .
. . 64
“ IV. RANGES,
. .
. .
. .
. . . 67
“
V. RICOCHET,
. . .
. .
. . . .
. 80
“
VI. RECOIL,
. . . .
. . . .
. . . . 84
“ VII.
WINDAGE, . . .
. . . .
. . . . . 87
“VIII.GUNPOWDER,
. .
. .
. .
. 90
CONTENTS
PAGE
PART IX. PROJECTILES, . . . . . . . 98
“
X. LABORATORY STORES,
.
. .
. 118
“ XI.
PLATFORMS, .
.
.
- .
. 127
“ XIl. ARTILLERY CARRIAGES AND MACHINES, 131
“ XIII. PRACTICAL GUNNERY, . . . . 157
“ XIV. RIFLE CANNON, . . . . . 161
“ IV. MISCELLANEOUS, . . . . . 174
SEQUEL,—SERVING AND WORKING HEAVY ARTILLERY, 187
__________
THE following Report was made by the Committee appointed at a meeting of the staff of the Artillery School at Fort Monroe, Va., to whom the commanding officer of the School had referred this work:
Your Committee to which has been referred the consideration of the work of Captain Roberts, proposed as a textbook for the Artillery Scbool, beg leave to submit the fol- lowing Report, viz:
The work submitted by Captain Roberts, and entitled “Hand-book of Artillery,” embraces sections on the following subjects.
(For subjects see Table of Contents, page 5.)
Under each of these heads, except the last, the work contains a number of questions and answers. Your Committee have carefully examined each of these questions and their corresponding answers, and find that the answers have been principally drawn from the following sources, viz.:
Gibbon’s Artillerist’s Manual, Light and Heavy Artillery Tactics, and the Ordnance Manual, all of which works have been authorized by the War Department. Wherever the
prescribed authorities furnish the means of answering the questions, they appear to have been followed as closely as possible.
In the opinion of your Committee, the arrangement of the subjects and the selection of the several questions and answers have been judicious. The work Is one which, may be advantageously used for reference by the officers, and is admirably adapted to the instruction of non-commissioned officers and privates of Artillery.
Your Committee do therefore recommend that it be substituted as a text-book in place of “Burns’ Questions and Answers on Artillery.”
(Signed) I. VOGDES,
CAPT. 1ST ART’Y.
(Signed) E. 0. C. ORD,
CAPT. 3D ART’Y.
(Signed) J. A. HASKIN,
Bvt. MAJ. AND CAPT. 1ST ART’Y.
The preceding Report
was adopted, and the Staff recommended this work as a book of instruction at
the Artillery
School, in lieu of “Burns’ Questions and Answers on Artillery.”
THE
HAND-BOOK OF ARTILLERY.
_____________
PART I. SECTION I.
1. What is understood by the term ARTILLERY?
Heavy pieces of every description with the implements and materials necessary for their use.
2. how many kinds of pieces are employed in the land service of the United ,States?
Four, viz.: Guns, Howitzers, Columbiads, and Mortars.
3. How are these distinguished?
According to their use, as Sea-coast, Garrison, Siege, and Field Artillery.
4. What metals are used in their construction?
All heavy pieces, such as those for sea-coast, siege, and garrison equipment, are made of iron; and those for field service, of bronze.*
5. What is bronze for cannon?
An ALLOY consisting of 90 parts of copper and 10 of tin, allowing a variation of one part of tin more or less. It is commonly called brass.
* The 3-in rifled filed gun, lately adopted, is made of wrought iron or steel.
HAND-BOOK OF ARTILLERY.
6. Why is bronze used in preference to iron, for field pieces?
This metal, having greater tenacity and strength than iron, the pieces can be made lighter.
7. In what respect does
iron merit a
preference?
Iron is less expensive than bronze, and is more
capable of sustaining long-continued firing with larger charges; such pieces
are, therefore, better calculated for the constant heavy firing of sieges.
NOTE.—In
the sieges In Spain, bronze guns could never support a heavier fire than 120
rounds in twenty-four hours, and were never used to batter at distances
exceeding 300 yards; whereas, with iron guns, three times that number of rounds
were fired with effect, from three times the distance, for several consecutive
days, without any other injury than the enlargement of their vents. The
comparative power of conducting heat in iron and copper being respectively as
3.743 to 8.932, taking gold at 10.000, it is evident that in practising with
iron and bronze pieces of the same calibre, it would soon become necessary to
reduce the charges in the bronze pieces, and, also to increase the time between
the discharges, to prevent their softening and drooping; while with iron, full
charges and rapid firing may be kept up.
8. What additional objection has been urged to bronze for cannon?
The difficulty of forming a perfect alloy, in consequence of the difference of fusibility of tin and copper.
9. What iron pieces are used in the land service?
3-in. (rifled)fieId gun; 41/2-in. (rifled), 12, 18, and 24-pdr. siege and garrison guns; 32 and 42-pdr. sea-coast guns; 8-in, siege and 24-pdr. garrison howitzers; 8 and 10-in, sea-coast howitzers; 8, 10, and 15-in. columbiads; 8 and 10-in.siege, and 10 and 13-in. sea-coast mortars,
ARTILLERY IN GENERAL.
10. What are the kinds of bronze pieces in use at present?
6 and 12.pdr. field guns; 12-pdr. Mountain howitzer; 12, 24, and 32-pdr. field howitzers; and the 24-pdr. Coehorn mortar.
11. What is a battery?
This term is applied to one or more pieces, or the place where they are served.
12. What regulate the dimensions of a piece?
Its calibre and the tenacity and elasticity of’ the metals employed in its fabrication. Its thickness must be pro-portioned to the effect developed by the powder; and the length is determined by experiment, and should not exceed 27 calibres. The exterior surface of a cannon is composed of several surfaces, more or less inclined to the axis of the bore, the forms of which have been determined by experiment.
13. Why is a piece made stronger near the breech than towards the muzzle?
Because the elastic force of the inflamed gun powder is there greatest, constantly diminishing in intensity as the space increases in which it acts.
14. What is the length of a piece?
The distance from the rear of the base-ring to the face of the piece.
15. What is the extreme length?
From the rear of the cascable to the face.
16. What is the BORE of apiece?
It includes the part bored out, viz.: the cylinder, the chamber (if there is one), and the conical or spherical surface connecting them.
17. What is understood by the CALIBRE of a piece
HAND-BOOK OF ARTILLERY.
The diameter of the bore.
18. How do you ascertain
the number of calibers in a piece?
Divide the length of
the cylinder, in inches, by the number of inches in the calibre.
19. The number of calibre, being known, howdo you find the length of the cylinder?
Multiply the number of calibres by the calibre in inches.
20. What is meant by the SIGHTS of a piece?
Artificial marks on the piece for determining the line of fire.
21. How are the sights determined?
Usually by means of the gunner’s level, when the trunnions are perfectly horizontal.
22. What is the LINE OF METAL or the natural line of sight?
A line drawn from the highest point of’ the base-ring to the highest point of the swell of the muzzle, or to the top of the sight, if’ there be one.*
23. What is the axis of apiece?
The central line of the bore.
24. What is the NATURAL ANGLE OF SIGHT?
The angle which the natural line of sight makes with the axis of the piece.
25. What is the DISPART of a piece?
It is the difference of the semi-diameter
of the base-ring and the swell of the muzzle, or the muzzle-band. It is,
therefore, the tangent of the naturalangle of sight to a radius equal to the
distance from the rear of the base-ring to the highest point of the swell of
the muzzle, or the front of the
*The
line of sight nearest the axis of the piece Is the natural line of sight;
the others are artificial lines of sight.
ARTILLERY IN GENERAL.
muzzle-band, — the case may be, measured parallel to the axis.
26. Give the nomenclature of a piece.
The CASCABLE is the projection in rear of the breech, and is composed of the knob, the neck, and the fillet.
The BASE OF THE BREECH is a frustum of’ a cone, or a spherical segment forming the rear surface of the breech.
The BASE-RING* is a projecting band of metal adjoining the base of the breech, and connected with the body of the gun by a concave moulding.
The BREECH is the mass of solid metal behind the bottom of the bore, extending to the cascable.
The REINFORCE is the thickest part of the body of the gun, in front of the breech; if there be more than one reinforce, that which is next the breech is called the first reinforce; the other the second reinforce.
The REINFORCE BAND IS at the junction of the first and second reinforces.
The CHASE is the conical part of the gun in front of the reinforce.
The ASTRAGAL AND FILLETS in field guns, and the chase ring in other pieces, are the mouldings at the front end of the chase.
The NECK is the smallest part of the piece in front of the astragal or the chase ring.
The SWELL OF THE MUZZLE is the largest part of the gun in front of the neck. It is terminated by the muzzle mouldings, which, in field and siege guns,
* This hasdispensed with in the brass 12-pdr. of the new pattern (the NapoIeon gun), and in the new model columbiads. All projections on the surface of cannon which are not required for the service of the piece, have been omitted in the late models.
HAND-BOOK OF ARTILLERY
consist of the lip and fillet. In sea-coast guns and with heavy howitzers and columbiads, there is no fillet. In field and siege howitzers, and in mortars, a muzzle-band takes the place of the swell of the muzzle.
The FACE of the piece is the terminating plane perpendicular to the axis of the bore.
The TRUNNIONS are two cylinders at or near the centre of gravity of a gun, by which it is supported on its carriage. The axes are in a line perpendicular to the axis of the bore, and, in our guns in the same plane with that axis.
The RIMBASEs are short cylinders uniting the trunnions with the body of the gun. The ends of the rimbases, or the shoulders of the trunnions, are planes perpendicular to the axis of the trunnions.
The BORE of the piece includes nil the part bored out, viz. the cylinder, the chamber (if there is one), and the conical or spherical surface connecting them.
The CHAMBER in howitzers, columbiads, and mortars, is the smallest part of the bore, mid contains the charge of powder. In the howitzers and large columbiads,+ the chamber is cylindrical; and is united with the large cylinder of the bore by a conical surface; the angles of intersection of this conical surface with the cylinders of the bore and vent chamber, are rounded (in profile) by arcs of circles. In the siege howitzer, the chamber is united with the cylinder of the bore by a spherical surface, in order that the shell may, when necessary, be inserted without a sabot.
The BOTTOM OF THE BORE (to facilitate sponging) is a plane perpendicular to the axis, united
*By a late order of the War Department, the swell of the muzzle is to be omitted in sea-coast cannon.
+The new columbiad is made without a chamber.
ARTILLERY IN GENERAL
with the sides (in profile) by an arc of a circle the radius of which is one-fourth of the diameter of the bore at the bottom. In the columbiads and the heavy sea-coast mortars, the bottom of the bore is hemispherical.*
The MUZZLE, or mouth of the bore, is chamfered a depth of 0.15 inch to 0.5inch varying with size of the bore), in order to prevent abrasion, and to facilitate loading. The TRUE WINDAGE is the difference between the true diameters of the bore and of the ball.
27. What is the vent?
The aperture through which fire is communicated to the charge.
28. What is to be observed in reference to the diameter of the vent?
It should be as small as the use of the priming wire and tube will allow.
29. Why?
As the velocity of the gases arising from the combustion of the powder is extremely great, a large amount escapes through the vent, which contributes nothing to the velocity of the projectile. It therefore follows, that the effect produced by a given charge will diminish as the diameter of the vent increases. Besides, on account of the increase of power in the current that escapes from them, large vents are more rapidly injured than small ones
30. What is the diameter of the vent?
0.2 of an inch in all pieces.
31. What is the position of the axis of the vent?
* In the late models, the bottom of the bore is a semi-ellipsoid.
HAND-BOOK OF ARTILLERY.
In the old models it is in a plane passing through the axis of the bore, perpendicular to the axis of the trunnions. In guns, and in howitzers having cylindrical chambers, the vent is placed at an angle of 80o with the axis of the bore, and it enters the bore at a distance from the bottom equal to one-fourth the diameter of the bore. The vents of columbiads and mortars of the model of 1881 are in planes parallel to the plane passing through the axis of the bore, and perpendicular to that of the trunnions, and at a distance from it equal to one-half the radius of the bore. The vents are perpendicular to the axis of the bore; the one on the right of the axis is not bored entirely through to the bore by one inch. The vent of the field and siege pieces of the model of 1861 is at right angles to the axis and in the plane passing through it per. vatic perpendicular to that of the trunnions.
32. What are the QUARTER-SIGHTS of a piece?
Divisions marked on the upper quarters of the base ring, commencing where it would be intersected by a plane parallel to the axis of the piece, and tangent to the upper surface of the trunnions.
Note.—Not used In our service.
33. To what use are the quarter-sights applied?
For giving elevations up to three degrees; but especially for pointing a piece at a less elevation than the natural angle of sight.
34. What is a BREECH SIGHT?
An instrument having a graduated scale of tangents, by means of which any elevation may be given to a piece.
35. How are the divisions of the tangent scale found?
ARTILLERY IN GENERAL.
Bytaking the length of the piece, from the rear of the base-ring to the swell of the muzzle, measured on a line parallel to the axis, and multiplying it by the natural tangent of as many degrees as may be required; and then deduct the dispart. Thus, for 50 elevation, and the gun supposed to be 5 feet, or 60 inches long, multiply .08748, which is the natural tangent of 50, by 6O; the product gives 5.2488 inches; supposing the dispart to be 1 inch, the graduating of the tangent scale will be 4.2488 inches.
36. With what pieces are breech-sights used?
Guns and howitzers.
37. What is a PENDULUM IIAUSSE?
It is a tangent-scale, the graduations of which are the tangents of each quarter of a degree of elevation, to a radius equal to the distance between the muzzle-sight of the piece, and the axis of vibration of the hausse, which is one inch in rear of the base-ring. At the lower end of the scale is a brass bulb filled with lead. The slider which marks the divisions on tile scale is of thin brass, and is clamped at any desired division on the scale by means of a screw. The scale passes through a slit in a piece of steel, with which it is connected by a screw, forming a pivot on which the scale can vibrate laterally. This piece of steel terminates in pivots, by means of which the pendulum is sup ported on the seat attached to the gun, and is at liberty to vibrate in the direction of the axis of the piece. The seat is of metal, and is fastened to the base of the breech by screws, so that the centres of the steel pivots of vibration shall be at a distance
ARTILLERY IN GENERAL.
from the axis of the piece equal to the radius of the base-ring.
A MUZZLE-SIGHT of iron is screwed into the swell of the muzzle of guns, or into the middle of the muzzle-ring of howitzers. The height of this sight of a is equal to the dispart of the piece, so that a line joining the muzzle-sight and the pivot of the tangent-scale is parallel to the axis of the piece.
38. What is a GUUNER’S-LEVEL, or gunner’s perpendicular!
An instrument made of sheet-brass; the lower part is cut in the form of a crescent, the points of which are made of steel; a small spirit-level is which fastened to one side of the plate, parallel to the line joining the points of the crescent, and a slider is fastened to the same side of the plate, perpendicular to the axis of the level.
39. What is it used for?
To mark the points of sight on pieces.
40.What is a PLUMMET?
A simple line and bob
for pointing mortars.
41. What is a GUNNER’S QUADRANT?
It is a graduated quarter of a circle of sheet-brass of 6 inches radius, attached to a brass rule 22 inches long. It has an arm carrying a spirit level at its middle, and a vernier at its movable end. To get a required elevation, the vernier is fixed at the indicated degree, the brass rule is then inserted in the bore parallel to the axis of the piece; the gun is then elevated or depressed until the level is horizontal.
There is another graduated quadrant of wood, of 6 inches radius, attached to a rule 23.5 inches long. It has a plumb-line and bob, which are car-
ARTILLERY IN GENERAL.
red, when not in use, in a hole in the end of the rule, covered by a brass plate.
42. What is an ELEVATING ARC, and its use?
It is an arc attached to the rear part of the cheek of a gun-carriage, having its centre in the axis of the trunnions; the arc is graduated into degrees and parts of a degree. By placing the axis of the piece horizontal, and marking the breech at any of the divisions on the arc, any elevation or depression required will be noted by the number of degrees below or above this mark. It turns on a pivot which admits of the arc, when not in use, being placed inside the cheek to which it is attached.
43. What is the use of the cascable?
To facilitate the handling of the piece in mounting and dismounting it, and moving it when off its carrIage.
44. Of what use are the trunnions of a piece? By means of them the piece is attached to its carriage; and by being placed near the centre of gravity, it is easily elevated or depressed.
45. What are the dolphins of a piece?
Two handles* placed upon the piece with their rule centres over the centre of gravity, by which it is mounted or dismounted.
46. Are all pieces provided with dolphins ?
Only the 12-pdr. brass guns, and the 24 and 32-pdr. brass howitzers.
47. What is understood by the preponderance of a piece?
It is the excess of weight of the part in rear of the trunnions over that in front; it is measured by
* In the heavy sea-coast mortars they are replaced by a clevis attached to a projection on the piece.
HAND-BOOK OF ARTILLERY.
the lifting force in pounds, which must be applied at the rear of the base-ring to balance the piece when suspended freely on the axis of the trunnions?
48. Why is this preponderance given?
To prevent the sudden dipping of the muzzle, In firing, and violent concussion on the carriage at the breech.
49. What is bushing a piece of artillery?
Inserting a piece of metal about an inch in diameter (near the bottom of the bore), through the centre of which the vent has been previously drilled. It is screwed in.
50. What kind of metal is used for bushing bronze pieces?
Pure copper always, which is not so liable to run
from heat as gun metal.
51. What is the object of bushing a piece?
To prevent deterioration of the vent, or provide a new one when this has already occurred.
52. Is all new artillery bushed?
No, only rifled and bronze pieces.
53. How are vents replaced?
The vent-piece in bronze and rifled pieces is taken out, and a new one screwed in. In other pieces the vent is filled up by molten zinc, clay being placed on the head of a rammer, and pressed against the upper surface of the bore, so as to close the vent on the interior, and a new one is bored two or three inches from the first.
54. How is artillery rendered unserviceable?
Drive into the vent a jagged and hardened steel spike with a soft point, or a nail without a
*Heavy pieces of the latest models have no “preponderance.”
ARTILLERY IN GENERAL.
head; break it off flush with the outer surface and the point inside by means of the rammer.
II. Wedge a shot in the bottom of the bore by wrapping it with felt, or by means of iron wedges, using the rammer or a bar of iron to drive them in.
Ill. Cause shells to burst in the bore of bronze guns.
IV. Fire broken shot from them with large charges.
V. Fill the piece with sand over the charge, to burst it.
VI. Fire a piece against another, muzzle to muzzle, or the muzzle of one to the chase of the other.
VII. Light a fire under the chase of a bronze gun, and strike on it with a sledge, to bend it.
VIIl. Break off the trunnions of iron guns; or burst them by firing them at a high elevation, with heavy charges and full of shot.
55. State how to unspike a piece.
If the spike is not screwed in or clinched, and the bore is not impeded, put in a charge of powder ½ of the weight of the shot, and ram junk wads over it; laying on the bottom of the bore a slip of wood, with a groove on the under side containing a strand of quick-match, by which fire is communicated to the charge. In a brass gun, take out some of the metal at the upper orifice of the vent, and pour sulphuric acid into the groove, and let it stand some hours before firing. If this method, several times repeated, is not successful, unscrewthe vent piece if it be a brass gun; and if an iron one, drill out the spike, or drill a new vent.
HAND-BOOK OF ARTILLERY.
56. Explain how to drive out a shot wedged in the bore?
Unscrew the vent piece, if there be one, and drive in wedges so as to start the shot forward, then raM it back again in order to seize the wedge with a hook; or pour in powder, and fire it after replacing the vent piece. In the last resort, bore a hole in the bottom of the breech, drive out the shot, and stop the hole with a screw.
Note.- When a shot is jammed is a gun and cannot be rammed home to the cartridge, destroy the charge by pouring water down the vent and muzzle until the ingredients we dissolved, and cleared out of the bore; then introduce a small quantity of powder through the vent, and blow out the shot.
57. Explain how to use a piece which has been spiked?
Insert one end of a piece of quick-match into the cartridge, the other being allowed to project from the muzzle. Apply the fire to the match and get out of the way. When quick-match of sufficient length is not at hand, insert one end in the cartridge, the other projecting in front of the shot, and throw two or three pinches of powder into the bore, after they are rammed home. Place another piece of match in the muzzle, one end projecting out. The fire is applied without danger.
58. What is sealing a piece of artillery?
Flashing off a small quantity of powder to clean out the bore; about 1/12 of the shot’s weight. The practice is discontinued.
59. How are cannon of the old model. in our service marked?
As follows, viz.: The number of the gun and
ARTILLERY IN GENERAL.
the initials of the inspector’s name on the face of muzzle,—the numbers in a separate series for each kind and calibre at each foundry; the initial of the name of the founder, and of the foundry number on the end of the right trunnion; the year of fabrication on the end of the left trunnion; the foundry number on the end of the right rim base, above the trunnion; the weight of the piece in pounds on the base of the breech; the letters U. S. on the upper surface of the piece, near the end of the reinforce.
60. How are the new pieces marked?
As follows, viz.: the number of the gun, the initials of the inspector’s name, and that of the foundry, the year of fabrication, and the weight of the piece in pounds on the face of the piece, in a circle concentric with the bore, in letters and figures at least one inch long; the numbers, in a separate series for each kind and calibre at each foundry; the foundry number, in small figures, on the end of the right rim base, above the trunnion; the letters U. S., in large characters, on the upper surface of the piece, in rear, but near the trunnions.
61. What marks are used to designate condemned pieces?
Pieces rejected on inspection are marked X C on the face of the muzzle; if condemned for erroneous dimensions which cannot be remedied, add X D; if by powder proof, X P.
62. What are the kinds of proof which artillery must undergo, before being received into the service?
1st. They are gauged as to their several dimensions, internal and external; as to justness and position of the bore, the chamber, vent, trunnions, &c.
HAND-BOOK OF ARTILLERY.
2d. They are fired with a regulated charge of powder and shot, being afterwards searched to discover irregularities or holes produced by the firing.
3d. By means of engines, an endeavor is made to force water through them.
4th. They are examined internally, by means of light reflected from a mirror.
63. Are brass cannon liable to external injury, caused by service
They are little subject to such injury, except from the bending of the trunnions sometimes, after long service, or heavy charges.
NOTE.—Recent experiments at Fort Monroe show that brass guns, when rifled, and fired with large charges and heavy shot, expand so much that the projectile does not take the grooves.
64. What are the causes of internal injury?
Internal injuries are caused by the action of the elastic fluids developed in the combustion of the powder, or by the action of the shot in passing out of the bore. These effects generally increase with the calibre of the piece.
65. Name the principal injury of the first kind?
The cutting away of the metal of the upper surface of the bore over the scat of the shot.
86. Name those of the second kind?
The lodgment of the shot,— a compression of the metal on the lower side of the bore, at the seat of the shot, which is caused by the pressure of the gas escaping over the top of the shot. There is a corresponding burr in front of the lodgment; and the motion thereby given to the shot causes it to strike alternately on the top and bottom of the bore, producing other enlargements, generally three
ARTILLERY IN GENERAL.
in number: the first, on the upper side a little in advance of the trunnions; the second, on the lower side about the astragal; the third, in the upper part of the muzzle; it is chiefly from this cause that brass guns become unserviceable. Scratches, caused by the fragments of a broken shot, or the roughness of an imperfect one.
67. When is a piece said to be honeycombed?
When the surface of the bore is full of small holes and cavities.
68. To what is this due?
To the melting and volatilization of a portion of the tin in the alloy; tin being much more fusible than copper.
69. How may the durability of bronze guns be increased?
By careful use, and by the precautions of increasing the length of the cartridge, or that of the sabot, or using a wad over the cartridge, in order to change the place of the shot; by wrapping the shot in woollen or other cloth, or in paper, so as to diminish the windage and the bounding of the shot in the bore. In field guns, both bronze and iron, the paper cap which is taken off the cartridge should always be put over the shot.
70. To what injuries are iron cannon subject?
To the above defects in a less degree than brass, except the corrosion of the metal, by which the vent is rendered unserviceable from enlargement. The principal cause of injury to iron cannon is the rusting of the metal producing a roughness and enlargement of the bore, and increase of any cavities or honeycombs which may exist in the metal.
HAND-BOOK OF ARTILLERY.
71. How may you judge of the service of an iron gun!
Generally by the appearance of the vent. After about 500 rounds the vent, becomes enlarged to 0.3 inch, and should not be used any longer. In rifled guns the wear of the vent is about twice as great as in smooth bore guns.
72. What rules are laid down for the preservation of artillery.
Cannon should be placed together, according to kind and calibre, on skids of stone, iron, or wood, laid on hard ground well rammed and covered with a layer of cinders or of some other material to prevent vegetation. In case of guns and long howitzers, the pieces should rest on the skids in front of the base ring and in rear of the astragal, the axis inclined at an angle of 40 or 50 with the horizon, the muzzle lowest, the trunnions touching each other; or the trunnion of one piece may rest on the adjoining piece, so that the axis of the trunnions may be inclined about 450 to the horizon; the muzzle closed with a tompion or plug of dry wood, well saturated with oil or grease; the vent down, stopped with a greased wooden plug, or with putty or tallow. The pieces may be piled in two tiers, with skids placed between them exactly over those which rest on the ground - the muzzles of both tiers in the same direction and their axes preserving the same inclination. In case of short howitzers and mortars, the pieces should stand on their muzzles, resting on thick planks, the trunnions touching, the vents stopped.
73. What additional precautions should be observed in case of iron pieces?
ARTILLERY IN GENERAL.
They should be covered on the exterior with a lacker impervious to water; the bore and the vent should he greased with a mixture of oil and tallow, or of’ tallow and beeswax melted together and boiled to expel the water. The lacker should be renewed as often as necessary, and the grease at least once a year. The lacker and grease should a applied in hot weather. The cannon should be frequently inspected, to see that moisture does not collect in the bore.
HAND-BOOK OF ARTILLERY
PART I. SECTION II.
I. What are GUNS?
Long cannon without chambers.
2. How are guns denominated!
Smooth bore guns by the weight of their respective shot; and rifled guns by the diameter of the bore in inches. -
3. What are the principal parts of a gun?
The cascable, breech, reinforce, chase and muzzle.
4. What proportion usually exists between the length and calibre of a gun?
It varies from 15 to 27 calibres.
5. What is the natural angle of sight in smooth-bore siege and garrison guns ?
One degree and thirty minutes.
6. What is it in smooth-bore field guns?
One degree in all except the new 12-pdr., in which it is one degree and six minutes.
7. Why have sea-coast guns no natural line of sight?
Because the swell of the muzzle is not visible when the eye is on a level with the base-ring.
NOTE—A natural line of sight may be formed by affixing
a front eight to the muzzle, or to a projection cast on time
piece between the trunnions.
GUNS.
8. Upon what are guns mounted?
On field, siege, barbette orcasemate carriages.
9. What projectiles are used with guns?
Solid shot, shells, spherical-case, grape, and canister.
10. About what are the weights of the different guns?
6-pdr., 884 lbs.; brass 12-pIr., 1,737 lbs., new pattern 1,220 lbs. ; iron 12-pdr., 3,510 lbs., 18-pdr., 4,913 lbs.; 24-pdr., 5,790 lbs.; 32-pdr, 7,200 lbs. ; 42.pdr., 8465lbs. ; 3-in. (rifled) field, 820 lbs.; 44-in. (rifled) siege, 1,450 lbs.
11. Give the entire length of the several guns.
6-pdr. field gun, 65.6 inches; 12-pdr. field gun, 85 inches, new pattern 72.15 inches ; 12-pdr. iron gun, 116 inches ; 18-pdr., 123.25 inches; 24-pdr., 124 inches; 32-pIr., 125.2 inches; 42-pdr., 129 inches ; 3-in. (rifled) field, 73.3 inches; 4-in. (rifled) siege, 133 inches.
HAND-BOOK OF ARTILLERY.