77. When field-pieces are landed, the guns shall be numbered from the right in the same manner as a company.

78. One or more armorers should be sent with each landing party with cleaning-rods, screw-drivers, and spare nipples.

79. The boats should be formed in divisions, according to the seniority of the Captains of their respective ships—or of the Commanding Officers of the divisions—numbering from the right. The seamen and marines, having been told off in companies previous to leaving their ships, on landing they will form immediately in the same order.

80. The howitzers being mounted as boat's guns and prepared for landing are brought at once into action, or remain in the boats, according to circumstances.

81. Each division of boats should have a distinguishing flag; and scaling-ladders, intrenching tools, and other implements, should be carried by designated boats.

82. The boats will always land a boat's length apart. Before leaving the ship four boat-keepers should be appointed to each boat carrying a howitzer, and two for the others, with an officer in charge of each division of boats, who are on no account to leave them. Should there be a probability of the landing party being attacked on a re-embarkation, the boats should be hauled off to their anchors, with a long scope of cable, having a stern-line to the beach, and a man in the boat to veer in, that the troops may be readily embarked. The officer left in charge of the boats should be careful to avoid being surprised; and, if circumstances admit, strengthen his position by cutting down trees and throwing up small breastworks a short distance in front.

83. A fast-pulling boat with Medical Officers will attend in rear of the line, designated by a yellow flag.

84. Should the distance from the point of landing be considerable, the boats of each division, in tow of each other, lightest boats leading, will fall in—the leading boat of each division abreast (Art. 72), leaving space for the whole line to form abreast when ordered. On approaching the beach the tow-ropes should be cast off, and the launches with howitzers dress up in line ready to open fire, if necessary, to clear the landing. The officer in command will commence firing from the howitzers when he thinks fit; but no musketry is to be fired without special orders.

85. When the Commanding Officer perceives the beach to be clear, or when he considers it proper, he will order "Cease firing!" and direct the boats with skirmishers and light howitzers to pull in and land as quickly as possible. On landing they will immediately extend, advance, and seize the first cover near the beach, if there be any, but will not open fire till the Officer commanding them sounds "Commence firing." The main body then pull steadily in and land, forming line in rear of the covering party. The howitzers form on the flanks of their divisions, or as ordered. Pioneers and scaling-ladders as ordered. The main body being formed, will advance in line or column, according to circumstances, preceded by the skirmishers firing, if necessary. When firing in close order the front rank should fire kneeling, as, owing to the shortness of muskets, accidents frequently occur. Under certain circumstances, as advancing on an open beach, the boats might be employed on the flanks to cover the advance or retreat.

86. Should the boats be employed for the disembarkation of troops, the same arrangement should be made. It will then be desirable that every boat should carry a flag similar to that of the Commanding Officer of its division; and, when in large numbers, the boats should also be painted according to the colors of the flags, that the troops may readily know their own boats.

87. The re-embarkation should be conducted on similar principles to the disembarkation—the skirmishers and light howitzers extending in rear of the line, which will then pass through the intervals, forming again, if necessary, to support the skirmishers, who will retire firing, and re-form in rear of the line. The main body will then embark, followed by the covering party under cover of the boats' guns.

88. When landing in a heavy surf, the ammunition should be put in one or more small powder-tanks, with the lids well screwed down.



PART III.

ORDNANCE

AND

ORDNANCE STORES.



PART III.

CHAPTER I.

ORDNANCE AND ORDNANCE STORES.

1. All articles of Ordnance and Ordnance Stores, when duly delivered at any Navy Yard, are to be borne on the books of the Inspector of Ordnance, and duly accounted for, according to such regulations as may, from time to time, be established by proper authority.

2. He will make monthly estimates and requisitions for all materials and articles which may be required by the master workmen in the Ordnance Department, and which he may deem necessary; which requisitions are to be forwarded to the Chief of the Bureau for his approval.

No articles are to be purchased without previous requisitions, nor any to be used until duly inspected, approved, and receipted for.

Before reception, every article shall be carefully examined by the master workman in whose department it is required, and such other person as the Inspector shall appoint, and compared with samples, to see that it conforms to the standard, and is, in quantity and quality, as called for by the requisition or order of the Bureau for its delivery.

He will keep on hand standard Patterns and Drawings, approved by the Bureau of Ordnance, to which all articles of manufacture or issue shall strictly conform; notifying the Bureau of any discrepancies therefrom in articles received from other Yards, that unauthorized variations may be checked and the manufactures of each Yard be identical.

3. The Inspectors of Ordnance at all Navy Yards shall have the immediate custody of all articles appertaining to ordnance, and they shall be kept in suitable places, separate from the other articles in the Yard.

And they will promptly inform the Bureau of all orders received from Senior Officers, which may in the least affect the execution of the instructions given by the Bureau in relation to their duties.

4. Inspectors of Ordnance having charge of the articles above mentioned are, under the direction of the Commandant of the Yard, to be responsible for their being carefully attended to, and preserved from injury.

5. Whenever any of them shall require repairs, other than those which can be made in the ordnance workshops, the Inspector will apply to the Commandant of the Yard, or to the Bureau through him, for the necessary means to keep all articles in his charge in order and ready for service.

6. He shall require from master workmen employed on ordnance work reports in the required form (see blank forms) of the expenditure of materials and labor upon each and every object under their immediate superintendence, at which time they will make a return of all unexpended material on hand. They will also be responsible for all waste and improper use of material by those under their general superintendence.

7. The Inspector of Ordnance shall have authority over all master and other workmen employed on ordnance work, and direct all its details.

He will examine and certify to the correctness of all bills rendered for materials, supplies, or labor in the Ordnance Department, and examine and certify to the correctness of the pay-roll of all persons employed on ordnance work.

8. No Inspecting Officer or person employed by the Bureau is to show to, or leave in the way of persons not authorized by the Bureau, any drawing, descriptions, or dimensions of guns under contract, nor to permit the examination by such persons of the guns themselves.

9. The resident and other Inspectors are to inform the contractors of this strict requirement on the part of the Bureau, and to request them to cause it to be rigidly enforced by all persons under their control.

10. It is most positively forbidden to communicate any information whatever in relation to ordnance matters, or to show or describe ordnance work, of any description, to any person not in the employ of the government, unless by superior authority.

Inspectors are also directed not to hold correspondence in writing with manufacturers, contractors, or other parties in relation to ordnance supplies, unless specially directed by the Bureau.

Officers on Ordnance duty will give no official opinion, to Inventors or others, upon the merits of any invention appertaining to Ordnance, which may be submitted to them officially or unofficially for examination, unless by special direction of the Bureau of Ordnance.

All such opinions will be forwarded to the Bureau, to whom parties must be referred for information.

11. The Inspectors of Ordnance at the several Yards and stations are required to enjoin upon all their employes the strictest secrecy in relation to every thing connected with their duties. No information whatever is to be given to any one in relation to the prices of articles, the details of work, or the condition of ordnance or ordnance supplies.

Any breach of this order is to be followed by prompt dismissal from employment.

12. Whenever any ordnance stores shall be furnished to vessels, or for any other purpose, the Ordnance Officer shall take proper receipts for them from the officer to whom they are delivered. These receipts shall be signed at the Ordnance office, and the commander is required to ascertain before sailing if the proper officers have signed all receipts and vouchers.

13. The Ordnance Officer will deliver with them an Invoice of the number and cost of such stores, retaining a receipted duplicate, approved by the commander, to be forwarded to the Bureau of Ordnance.

One Ledger, one Invoice, and twenty blanks for Quarterly Returns to the Bureau of Ordnance, are to be furnished each vessel fitted for sea.

If any articles are purchased abroad, or obtained from other stations after the vessel is regularly fitted for sea, they should be duly entered in the Ledger, and a note made therein stating when, and from what source received; and, if practicable, their number and cost should be inserted in the Invoice of other articles supplied the vessel.

14. A separate list shall be furnished to all commanders of vessels of the ammunition furnished, which list is to be returned to the Ordnance Officer of the Yard to which the vessel shall return, with any additional supplies which she may receive during the cruise entered on it.

15. The allowances which are prescribed for the different classes of vessels in the Table of Allowances are not to be exceeded, except by the express sanction of the Chief of the Bureau of Ordnance.

16. It shall be the duty of any commander of a vessel, before making or approving requisitions, to examine the allowance table and expenditure books, to see that the amount required, together with that on hand, does not exceed the allowance, and that the articles required are allowed. If these articles are not allowed, or are in excess of the allowance, but are, in his opinion, necessary for the use of the ship under his command, he will state on the requisition, opposite the article, "in excess of allowance," or, "not allowed," and the reason why considered necessary, before sending it to the Commandant of the Yard or Squadron for his approval.

In case he shall neglect so to do, the Inspector of Ordnance will only furnish the allowance, and shall return the requisition for correction, calling the attention of the approving officer to this neglect.

17. All Ordnance Stores, except the ammunition, shall be delivered to the Gunner, or other officer appointed to receive them, at the ordnance store-houses, the Inspector of Ordnance furnishing him with the means of transportation, and men for stowing them in their appointed places on board, when the crew are not available for this purpose.

In order to guard against the loss or misdirection of Ordnance Stores, which has frequently been found to occur whilst they were being transferred from the Ordnance Store-houses to vessels going into commission, or in the case of vessels landing their stores on returning from a cruise:

The Bureau directs that whenever Ordnance Stores of any kind are to be received from or delivered on board of a vessel, a responsible officer be present, whose duty it shall be to take an exact account of them and see them safely delivered at their destination, indorsing the Receipts and Invoices with his name.

For any loss that may occur in the performance of this duty, that officer will be held pecuniarily responsible; and whenever any stores are found to be missing, the name of the officer who superintended their removal is immediately to be forwarded to the Bureau.

The Inspector of Ordnance will be vigilant in seeing this order strictly carried out.

18. All stores landed from ships will be received at the Ordnance Store-houses, when all responsibility on the part of the officer delivering them shall cease, and a survey be held, as soon thereafter as practicable, to determine the quantity of stores, and the condition in which they are delivered.—(See form of survey.)

When the vessel returns to a yard to be refitted or to be laid up at the end of the cruise, her Ledger and Invoice are to be handed to the Ordnance Officer of the yard for his examination, and for the use of the officers who may be ordered to hold a survey upon the Ordnance Equipments and Stores; and when the survey is completed, both Ledger and Invoice are to be forwarded to the Bureau of Ordnance with the report of survey.

19. It having been found that in the "Reports of Survey" made at the different Navy Yards on the Ordnance Stores of vessels returning from sea, many articles are put down as "deficient by Returns" without these deficiencies being in any way accounted for, the Bureau directs that the Surveying Officers shall require the Gunner (or other officer having charge of the Ordnance Stores, in case there be no Gunner on board) to show a just cause for said deficiencies; a statement of which, properly signed, is to be forwarded to the Bureau with the Report of Survey. In case of his failure to do so, he will be held responsible for the loss, and the value of the deficient articles checked against his pay.

Where arms or other articles are lost or destroyed in action, the fact must be properly authenticated by the signature of the Commanding or Executive Officer.

20. Ordnance Ledgers of all vessels coming from a cruise shall be signed by the Gunner or Executive Officer and the officer in command before leaving the Yard or station.

Invoices and Receipts must invariably be given and taken of all ordnance, ordnance stores, equipments, and small arms, when transferred from the keeping of one officer to another.

And whenever any article of ordnance is lost or mutilated, the fact shall be reported to the Bureau, with all the circumstances of the case, and the value of the same will be deducted from the pay of the person having it in his possession at the time, unless sufficient reason for a contrary course should appear.

21. It shall be the duty of the Inspector of Ordnance (or of the officers who inspect a ship on her return from a cruise) to report to the Bureau the condition in which the articles under the charge of the Gunner may be transferred, that his care and attention may be properly known and appreciated.

22. Officers upon Ordnance duty at Navy Yards may correspond with the Bureau on subjects connected with Ordnance duties, forwarding their communications open, to the Commandant of the Yard for transmission.

23. The dates of all circulars, orders, telegrams, or letters to which reference is made in corresponding with the Bureau, shall be distinctly quoted.

And the same rule is to be observed in forwarding triplicate Bills, Bills of Lading, and Invoices, the date of the order or orders being written across the face in red ink; and the receipt of all telegrams must be immediately acknowledged.

24. The Commandants will, in forwarding communications, accompany them with such remarks or recommendations as they may deem proper, and at any other time make such suggestions as they may consider will promote the public interest.

25. In shipping or forwarding stores each box or package shall be numbered, and have the nature of its contents stencilled or marked on the outside, and noted on the Invoice. The Invoice should in all cases of shipment accompany the articles.

All stores intended for shipment to squadrons, shall be legibly and conspicuously addressed to the Commander-in-Chief of the squadron, and marked for that squadron.

INSPECTION AND PROOF OF NAVAL GUNS

26. All cannon for the navy, cast at private foundries, will be fabricated in strict accordance with the terms of the contract made with the Bureau of Ordnance, and subject to the inspection of an officer detailed to supervise the operations. (See "Instructions for the Inspection and Proof of Cannon, 1864," for further details.)

27. New guns are to be closely examined and measured, inside and out, for defects of metal or manufacture, and the results recorded in the prescribed forms by the Inspector resident at the foundry, as soon after being finished as possible, if he has not already done so in the various stages of manufacture, which is preferable, as the detection of errors which pass the limits of toleration may save useless subsequent labor. Internal defects of metal will, for instance, generally be betrayed by a close examination of the core-pieces. As rust tends to conceal defects, this examination of the guns is to take place before exposure to the weather. And previously to the final examination and proof of guns, they are not to be covered with paint, lacquer, oil, or any material which may hide defects of metal.

If it is ascertained that any attempt has been made to conceal defects, the gun or guns so treated are to be rejected without further examination.

As the water-proof, which is of great importance in detecting defects of metal not otherwise developed, necessarily succeeds immediately the powder-proof, and can be effectively applied only in fine weather, and when the temperature is above the freezing-point, final inspections are to be made at such times only.

DESCRIPTIVE LIST OF INSTRUMENTS REQUIRED AND USED IN THE INSPECTION AND PROOF OF GUNS.

28. 1st. A mirror for reflecting the sun's rays into the bores. Two will be required if the sun be in the rear of the Inspector.

2d. A lamp attached to a staff for examining the bores when the sun is obscured, or the guns are under cover.

3d. A standard cylinder gauge. This is a hollow cylinder of iron, turned to the least allowed diameter of the bore, and one calibre in length. It has a cross-head at each end, one of which has a smooth hole through its axis to fit the staff, and the other is tapped to receive the screw in the end of it.



4th. A measuring-staff of steel or iron, in joints of suitable length, connected together by screws. Each joint is provided with a light brass disk, the diameter of which is 0.05 inches less than that of the bore. Through the centre of the disk there is a hole which fits upon a shoulder at the joint; the whole is so arranged that when the joints are screwed together the disks between them are held firmly in place, while the length of the staff is not affected by them. A steel point is screwed on to the end. When pushed to the bottom of the bore, the staff coincides very nearly with its axis. The outer joint is graduated to inches and tenths. A slide is made to play upon it with a vernier scale, graduated to hundredths of an inch. On the inner end of the slide a branch projects at a right angle, sufficiently long to reach across the muzzle face, and, when in contact with it, to indicate the precise length obtained from that point to the end of the measuring-point on the other end of the staff. A half disk of wood, made to fit the bore, with a groove for the staff to rest in, placed just inside of the muzzle, is useful in preventing any springing of the staff.

The point being taken off, the staff can be used with the cylinder gauge, to measure the distance to which the latter descends. But as the graduation is intended for the points, care must be taken in this case to allow for the difference.

5th. A chamber-gauge for verifying the shape and size of conical chambers.

The head should be made of close-grained, well-seasoned wood, and of the exact dimensions of the chamber. Two planes, crossing each other at a right angle, coinciding with the vertical and horizontal central sections, have been found better than a solid block. The edges should be bevelled. A metal socket in its centre connects it with the measuring-staff. Being pushed to the bottom of the bore, if the length coincides with that obtained by the point, it is obvious that the chamber is large enough, provided the cylindrical part has not been bored too deep, in which case a shoulder would be found at the junction. The edges of the gauge should be chalked before it is inserted. When withdrawn, if the chalk-marks are visible all around the chamber, it is evident the chamber is not too large. With slight modifications, this arrangement may be applied to the slope of cylindrical chambers, and to the curve at the bottom of the bore of any guns. Should the inspection of guns with conical chambers or slopes take place at the foundry, an examination of the chamber reamer will be very satisfactory. If found correct in size and shape, the impossibility of making the chamber too large will be apparent.

6th. A star-gauge, for measuring the diameters of the bores and of cylindrical chambers. This instrument is composed of the staff, the handle, and a set of points for each calibre.

The staff is a brass tube, made in three pieces, for convenience of stowage, and connected together, when required, by screws. Its inner end expands into a head, in which are placed four steel sockets, at equal distances from each other, which receive the points. Two of the sockets opposite to each other are secured permanently. The two others are movable. A tapering plate or wedge, the sides of which are cylindrical, runs through a slit in the head; an aperture in the inner ends of the movable socket embraces the cylinder, so that when the plate is moved forward or backward, the sockets are projected or withdrawn. The tapering of the plate has a certain known proportion to its length, so that if it is moved in either direction a given distance, a proportional movement is imparted to the sockets, and to the points which they contain. It is easy to see how, in this manner, a movement of .10 in. may increase or diminish the distance between the points .01 in. Therefore there would be no difficulty in estimating, to a considerable degree of accuracy, a difference of .001 in. between the points. In general, however, the distance on the plate required to move the points .01 in. is about .06 in. only.

A square sliding rod is connected with the tapering plate, and runs through the whole length of the tube, projecting some inches beyond the outer end. This rod has as many parts as there are joints in the staff, and, like them, connects by screws. Each section of the rod works in its proper joint, through a square socket at each end, and is prevented from falling out by pins. When screwing the joints together, if the ends of the rod are pressed up to each other they become connected by the same motion.

The staff is graduated to inches and quarters, so that the distance of the points from the muzzle of the gun may always be known. A centre line, starting from the centre of the upper socket, is marked upon the staff throughout its length.

The handle in use at present is of brass, made to fit over the outer end of the staff, and to connect with the sliding rod by a screw, having a large milled head at the outer extremity of the handle. It may be used on either joint, as required. A slit through the handle permits a part of the staff near the end to be seen beneath. A scale on one side of the slit is graduated with the distance that the rod moves, to throw the points .01 in. apart.

That part of the handle containing the slit and scale is separated from the other part; it is made to fit closely over it. On each side there is a small tube; a thread is cut in one, through which a fine screw, held by a stud on the permanent part of the handle, works and gives it motion; a guide runs through the other. Seen through the slit is a small plate of silver inserted in the staff, and a fine mark upon it to show the place of zero, when the points are adjusted. The zero-mark on the scale is made to correspond with it by means of the screw just mentioned.

The points are of steel, with a strong shoulder at one end, below which the screw is cut that fits into the socket in the head. A wrench is made to fit the other end, so as to turn the point firmly into its place. They are made of such a length that they will just pass into the adjusting-ring when they are all in place. To this instrument belong the adjusting-rings and the muzzle-rest in the form of T; of the rings there is one for each calibre, reamed out to the exact minimum diameter of the bore. The latter can be used for any class of guns. Its office is to keep the staff of the star-gauge in the axis of the bore. For this purpose it contains a groove, above the perpendicular branch, to receive the lower half of the staff. There is a movable slide on each branch, which can be adjusted to marks for each calibre, so that points projecting from their rear will enter the muzzle and hold the rest in place. In this position the upper edge of the transverse branch coincides with the diameter of the bore.

A hook is pivoted on the inner side of the transverse branch, on one side of the groove, and so fitted that when the star-gauge is in the gun, it embraces one-half of that portion of the staff which is above the groove. Therefore, if the transverse branch be placed so as to coincide with the axis of the trunnions, the hook thrown over the staff, and the latter turned so that the centre line just meets the end of the hook, the perpendicular points will be perpendicular to the axis of the trunnions. If the staff is then drawn out carefully, the measurements will all be taken in the same plane. A notch in the end of the hook, made to coincide with the plane of the muzzle, may be used for marking the distances on the staff.

The upright branch is movable, and is made to fit into the end of the transverse branch, for convenience and security in packing.

In examining the bores after proof, it has been found that the greatest indentation occurs in general near the seat of the projectiles. But, as it is not always found at precisely the same point of the circle of the bore, a convenient mode of searching for it is desirable. This is supplied by a disk for circular measurements, which may also be considered as belonging to the star-gauge. It is made of composition, and is divided into halves, with a hole through the centre to receive the staff of the star-gauge.

It is turned so as to fit into the muzzle of the gun closely, with a projecting lip two or three inches broad to hold it in place, and with cleats overlapping the edges, to keep it from going in too far. The face is a plane surface. The circumference is divided into as many equal parts as may be thought desirable, which are numbered in regular order. The centre hole is reinforced on the inside by a projection which is turned to receive a collar that fits closely around it, and holds the two halves together when they are placed on the staff.

When ready for use, the face is in the plane of the muzzle-face. Its zero-mark is made to coincide with a light punch-mark on the muzzle-face, directly below the line of sight.

On the staff of the star-gauge a brass slide is fitted, having a thumb-screw to hold it in any position; from the inner end a point extends at a right angle to its axis, of sufficient length to meet the points at the circumference of the disk; a centre line extends from the base to the apex. The slide being moved so as to make its inner end coincide with any mark upon the staff, at which a circular measurement is required, and the centre line of the point being made to coincide with that of the staff, it is secured by the thumb-screw. The point of the slide is then in the same plane with the perpendicular measuring-points, and its direction always indicates them; a series of measurements, made before proof, may thus be compared with another made at the same points after proof.

It is obvious that the determinations will not be absolutely accurate, for when the gun is worn, should the stationary points be perpendicular, the movable points, being then horizontal, would fall below the true horizontal diameter, and the measurements would be more in error than it would be with the points in any other direction. Still, if care is taken to preserve the points at the greatest length possible, a very tolerable degree of accuracy may be attained. In the inspection of guns arranged on skids, the gun itself should be turned, which will insure accurate measurements. Care must also be taken not to allow the joints of the staff to become so loose that the coincidence of the centre line is destroyed when they are screwed together. If this should occur, however, a few turns of thread, placed between them at the time of putting the instrument together, would remedy the difficulty.

7th. An instrument for verifying the interior position of vents.

When the vent is drilled in the vertical plane of the axis, as in the guns of old patterns, a simple head, shaped to fit the bottom of the bore, or the chamber, with a staff fitted to it, is sufficient. But for the Dahlgren guns, with two vents, some other plan is better. The following has been found satisfactory:

A head of well-seasoned wood, which is fitted to the chamber, is attached to a wooden disk of the diameter of the main bore. The surface of the head corresponds with a longitudinal central section of the chamber; at the point where the projection of the vent would meet it a piece of hard wood is inserted. A central line drawn through its length, crossed at a right angle by another line at any known point from the smaller end, will afford convenient points to measure from. A stout square wooden staff is attached to the axis of the head; at a distance equal to the length of the bore, the end is jogged into the centre of a half disk of wood, which is fitted to the bore. The whole is so constructed that the straight edge of the half disk (or the chord) is in the same plane as a horizontal section of the head. A few holes are bored through the disk attached to the half head, to allow the instrument to pass freely into the gun and out of it.

A wire of untempered steel, of the size of the vent, with a sharp, well-centred point, and a small spirit-level, are required to use with this instrument.

The gun being levelled, and the instrument being pushed to the bottom of the bore, the upper edge of the half disk near the outer end of the staff is then brought to a level. The surface of the half head then corresponds with the horizontal central section of the chamber. The point of the wire being pushed gently to meet it, will show very accurately the interior position of the vent.

8th. Profile-boards for distances in front and rear of the base line.

Their lower edges are adapted to the shape of the gun, and the upper ones are parallel to the axis of the bore.

The distances from the base-line of the several parts, and of the points at which diameters are to be measured, are laid off accurately on the upper edge, and then marked in lines perpendicular to it on the sides and lower edges of the profile. An iron strip is attached to the upper edge to prevent warping, and the whole is well coated with shellac varnish, to keep it from absorbing moisture.

The following instruments are used in connection with the profile-boards:

A rule for verifying the marks, of such a length that not more than one fleeting may be necessary, to be graduated decimally according to the standard.

A small square of steel, to be used in referring the marks on the board to those on the rule.

A steel straight-edge, long enough to extend across the muzzle-face, and several inches on the board, to ascertain the extreme length from base to muzzle. It is also used for the same purpose at the extreme end of the cascabel.

A steel scratcher, to mark the gun at points not otherwise indicated, where diameters are to be measured.

9th. A trunnion-square of steel or iron for ascertaining the position of the trunnions, with reference to the axis of the bore. This instrument is a square with two branches, one of which is fixed and the other movable. The foot of each branch is in the same plane, and is parallel to the upper edge of the main piece which connects them. The latter is graduated to inches and tenths. The movable branch slides on the main piece, and may be secured to it by two thumb-screws. It is provided with a vernier scale graduated to hundredths of an inch. Between the branches there is a slide, also provided with a vernier graduated as before, with a thumb-screw to secure it firmly; in its centre there is a sliding-point, moving vertically, with a thumb-screw to fasten it. Above the foot of each branch there is a slit to receive the shank of a plate, on the end of which a thread is cut; the lower edge of the plate forms a right angle with the branch, and the plate is fastened to the branch by a nut, at a point from the end equal to the semi-diameter of the trunnion, which is marked on each branch.

When the feet of the branches, or the lower edge of the plates, rest upon the trunnions, the upper edge of the main piece is parallel to their axis, if their alignment is correct. When in the latter position, the edges of the feet will lie close against the sides of the trunnions.

A graduated steel wedge is used to measure the deviation of the trunnions from the feet of the square.

10th. A trunnion-gauge, which is an iron ring of the proper diameter of the trunnions. Its outer edge coincides with the diameter of the rimbases.

11th. A trunnion-rule, to measure the distance of the trunnions from the base ring, or line. This is an iron rod with a head at one end, through which passes one branch of a small square. The centre of the rod is marked on the end, and the square is set so that the inner edge of the branch which is parallel to the rod is at a distance equal to the semi-diameter of the trunnion from the centre. It is secured in this position by screws and clamps.

The upper side of the rod is graduated to inches and tenths. A slide with a slot through it, to show the graduation beneath, traverses upon it, and is kept from turning by a guide on the lower side. There is a vernier upon the slide, graduated to hundredths of an inch; a thumb-screw serves to secure the slide at any point on the rod. That end of the slide from which the graduation of the rod commences has both of its sides drawn out, to form knife-edges; the knife-edges and the end of the slide are in the same plane. When the square at the end is placed on the trunnion, the end of the rod will touch its side at the point of its greatest diameter. The rod being held parallel to the axis of the bore, with the side of the head pressing the rimbase, the knife-edge will be in a proper position to fall into the base line when moved to find it.

12th. A beam-calliper for measuring diameters is a square of steel or iron, with two branches, one of which is fixed and the other sliding. The inner edges of the two branches, when pushed together, lie, of course, in contact with each other throughout their length. The beam is graduated to inches and tenths. A vernier is attached to the sliding branch, graduated to hundredths of an inch. The latter is provided with a thumb-screw, to fasten it at any point.

The length of the beam must be rather greater than the diameter; and that of the branches than the semi-diameter of the guns to be inspected, at their largest points.

13th. A cascabel-block is a wooden cylinder of the proper diameter of the breeching-hole, the size of which it is used to verify.

The opening between the jaws may be ascertained by measuring the iron block which is fitted to go between them, or by a template.

14th. A vent-guide, to be used with vents in guns of Dahlgren's pattern.

This instrument is made of bronze or composition. When placed upon the gun, one of its branches coincides with the curve of the cylinder, and the other, starting from its centre, lies along the cylinder in contact with it longitudinally. The lower edges of the branches are a right line and a curved line, making two right angles with each other. The length of that of the transverse branch is equal to the distance between the centre of the two vents. The rear surface of the transverse branch is curved and quadrilateral. Its sides are inclined, so that their rear edges show the exact direction of the vents. Every point in the upper edge lies in the same horizontal plane. The height is sufficient to permit the edges to give an accurate direction to the drill.

The upper edge of the other branch runs off in a sloping curve to its extremity.

A centre line is drawn through the lower edge of the longitudinal branch, and is continued upwards on the rear surface of the transverse branch to the top.

The guide being placed with its centre upon the centre mark of the gun, and the centre line of the longitudinal branch being made to coincide with the centre line scribed upon the cylinder, the rear lower edge of the transverse branch will then coincide with the base-line, its extremities will indicate the centres of the vents, and the rear edges of the sides will show their true direction.

15th. Vent-gauges of untempered steel wire, with shoulders to prevent them from slipping into the vent. One should be of the proper diameter of the vent, one of the greatest, and one of the least diameter allowed.

16th. A vent-searcher, a steel wire of the length of the vent, bent to a right angle at the lower end and pointed. It is used for detecting imperfections in the sides of the vents.

17th. A semicircular protractor of metal for measuring the inclination of vents, or for ascertaining their deviation from the guide.

18th. A set of templates for verifying the shape of lock-lugs, the angle of the rear sight mass, the curve between the base-line and the front of rear sight mass, that at the end of the cascabel, the bevel of the breeching-hole, the opening of the cascabel, and the shape of the muzzle swell.

If the inspection should take place at the foundry, the templates used in chipping might be verified and used for inspection.

For guns of Dahlgren's pattern, a bronze model, showing the shape of the lugs and rear sight mass, and the position of the vents, is furnished as a guide to the contractors.

19th. A standard foot-rule for verifying measures.

20th. A foot-rule of steel for measuring the masses, the length of the trunnions, and for other purposes. The graduation should be extended to each end.

21st. A set of ring-gauges, large, medium, and small, for inspecting the projectiles used in proof.

22d. A small beam-calliper, with outside edges, for examining the adjusting rings and the ring-gauges.

23d. A platform balance, for weighing the projectiles used in proof, and for bringing the shells up to the standard weight. For use with the above there should be provided a bag of dry sand, a funnel, some wooden plugs for the fuze-holes, and a hammer.

24th. A set of implements for loading and cleaning, viz.:

A rammer, faced with hard wood or metal, with a graduated scale on the staff, near the muzzle, to show the distance of the front of the projectiles from the muzzle. A bristle sponge with a worm in its end, for ordinary use in firing. A sheepskin sponge, for drying the bore after cleaning it. A gun-scraper. A ladle. A boring-bit. A priming-wire. A lock and lanyard, should navy primers be used in firing; but if friction primers are used, then a lanyard with a hook in its end will be required, only. A breeching and a couple of tackles, if the guns should be fired on skids. Six handspikes. Six buckets and a large tub, for washing out the guns.

If the firing is made into a butt, a couple of wheelbarrows, with two or three pickaxes and half a dozen shovels, will be necessary.

25th. A searcher, with six or more points, to detect injuries or cavities in the bore.

26th. A machine for taking the interior impression of vents.

This consists of a wooden head, one-half of which is cylindrical, and the other half is of the shape of the chamber, both being rather smaller than the parts of the bore that they are intended for. A staff, flat on its upper side, and rounded on its under side to fit the curve of the bore, is mortised into the circumference of the cylindrical part of the head. A mortise is cut through the chamber part of the head, extending several inches in rear and front of the position of the vent. Into this mortise a loose piece is fitted, capable of free motion upwards and downwards, the top of which is pierced with holes to secure the wax or composition which is spread over its surface. This movable piece rests on a wedge attached to a flat rod running through a slot in the head; there is a slot in this rod about four inches long, a pin passing through it into the staff. To use the instrument, withdraw the rod as far as the slot will permit, which will allow the movable piece on which the composition has been spread to drop below the surface of the head, and protect it. Push the head to the bottom of the chamber, and arrange the position of the staff so that the movable piece will cover the vent, then press the end of the rod home. This motion will throw out the composition, and a distinct impression of the vent and of fire-cracks (should there be any) will be left upon its surface; draw the rod back as far as the slot will allow, and withdraw the instrument: the impression, being protected thereby, will come out uninjured.

Impressions of injuries or cavities in the bore may easily be taken by a similar contrivance.

27th. Hydraulic pump and apparatus for the water-proof.

Any of the various patterns of this machine may be applied to the proof of guns. An iron cross-head is secured to a stout wooden block which fits into the muzzle, and which has a flange or shoulder to cover the muzzle-face; rings of caoutchouc or gutta-percha are placed between them; an iron rod with a ring in one end, to fit over the trunnion, and with a thread cut on the other end, is used on each side of the gun, to connect the trunnion with the cross-head. The whole is set up with nuts, and the pressure upon the rings makes a tight joint; a coupling upon the cross-head receives the hose, and the water is forced into the gun through a hole in the wooden block. Care should be taken that the valve is loaded with the proper weight for proof.

28th. Dies for marking guns.—A full set of figures, with such capital letters as may be required for the inspection-marks; these should be one inch in length. Also, small letters of suitable size to mark "lbs.," and a full set of half-inch figures.

USE OF THE INSPECTING INSTRUMENTS.

29. The guns having been freed from rust, and their foundry numbers noted, in the order of their relative positions, on the field-book, the inspecting officer will proceed to verify the instruments to be used in their measurement, if this has not been previously done in a manner entirely satisfactory to him.

He will then examine carefully the guns, inside and out, for defects of metal or of manufacture, and note the results.

The interior of the bore is to be examined by reflecting the rays of the sun into it from a mirror or mirrors; or, if the sun is obscured, and there can be no delay, by means of a spirit-lamp, or of a wax taper, on the end of a rod, taking care not to smoke the surface of the bore.

The cylinder-gauge is then to be introduced, which must pass freely to the bottom of the cylindrical part of the bore. If obstructed, the depth to which it reaches should be noted.

The star-gauge is used to ascertain the exact diameter of the bore, and of the cylindrical part of the chamber. The bore must be measured at intervals of 1/4 inch from the bottom of the cylindrical part to the seat of the shot; of 1 inch from that point to the trunnions; and of 5 inches from the trunnions to the muzzle. If any marks of the reamer or other defects are seen in the bore, they are to be searched for, and their depths and positions noted. These results are to be tabulated according to the blank forms furnished. The whole length of the bore is ascertained by means of the measuring-staff, with the point screwed on, supported in the axis of the bore by the disks and half-tompion.

In the absence of this instrument, a pine rod, having the proper length of the bore marked on it, and the end rounded to the curve of the bottom of the bore, will answer as well, using a thread or a straight-edge across the face of the muzzle.

The shape and dimensions of the chamber, and the position of the interior orifice of the vent, are verified by means of the chamber-gauge, the description of which will explain its use. An inspection of the chamber-reamer will be generally satisfactory in determining the size and shape of the chamber.

The vent is measured by the appropriate gauges, the smaller of which must enter freely, and the larger not at all. It is searched for roughness, or for cavities in the metal around it, by means of the searcher, the point of which should feel every part of it carefully.

Its inclination to the surface, and its position externally, are verified by means of the vent-guide furnished for the Dahlgren guns, and by the semicircular protractor and the vent-gauge.

In guns of the ordinary construction, the position of the vent is marked on the profile-board, and its inclination to the surface is determined by the protractor and vent-gauge.

The exterior lengths of the gun are measured by the profile-board, marked with the true dimensions, the differences being measured by the foot-rule, or, if minute, estimated by the eye.

The exterior diameters are measured with the calipers and square, or by the set-gauges used in turning, and a graduated wedge.

To verify the position and alignment of the trunnions of a gun, it is first necessary to ascertain, by means of the trunnion-gauge and of the calipers, their cylindrical form and their diameters, which should be the same, or allowance must be made for half the difference in measuring their axial distances from the base-line, by the trunnion-rule, which should next be done. These distances should be equal, or their axes do not coincide—an error not tolerated.

The trunnion-square is then placed upon the trunnions in the plane of their axis. The feet of its branches should coincide with the surfaces of both trunnions, throughout their length, above and in rear, and their inner edges with the faces of the rimbases. Then, with the beam-compass, scribe on the upper surface of the gun the distance of the axis of the trunnions from the base-line, and push the sliding-point of the square down, till, at that distance, it touches the surface of the gun, and screw it fast. Then turn the gun over, and again scribe on it the same distance from the base-line. The square, being again applied, will determine whether the trunnions are above or below the axis of the bore, which will coincide with that of the gun, if accurately bored, and turned on the same centres and bearings. If the branches rest upon the trunnions before the point of the slider touches the gun at the scribe, their axis is below; but if the point touch first, above the axis of the bore, by half the space between. The graduated wedge, being placed under the vertical sliding-point, will determine the amount. If both touch at once, both axes are in the same plane.

No gun can be received, the axis of the trunnions of which is above that of the bore.

The lengths of the trunnions are measured with the foot-rule, and the diameters of the rimbases by that of the exterior rim of the trunnion-gauge.

If the alignment of the trunnions be correct, it will serve as a means of determining the correctness of the line of sight, which, before the gun is removed from the lathe, should be distinctly traced on the sight-masses and the swell of the muzzle, and should be at right angles to the base-line, to the axes of the trunnions, and to the connecting piece of the trunnion-square, when its branches rest against their rear, with the plates across their upper surfaces.

The Inspector will further satisfy himself of the correct tracing of the line of sight on the gun, by examining the lathe and the manner of tracing it in the plane of the axis of the bore, at right angles to the axis of the trunnions, as by it are placed the sights and vent, and in their absence it serves as a line of metal sight.

The positions of the sight-masses are verified by the profile-board, and by reference to the line of sight, traced on them; their form and dimensions by the templates.

The positions of the lock-lugs and their forms are verified by means of the bronze pattern furnished to each foundry for each class of the Dahlgren guns, and their dimensions by the templates. For other guns the position of the lock-piece is marked on the profile-board, and their measures taken as above.

The opening of the cascabel and its curves, and those of the breech and the muzzle-swell, are verified by means of the "cylinder-block" and the templates.

30. The following variations from the proper dimensions may be tolerated by the Inspector, though every effort should be made to conform exactly to the drafts furnished by the Bureau of Ordnance.

In the diameter of the bore { more 0.03 { less 0.00

Exterior diameter { where turned } more .05 { or planed } less .05 { { where not } more .20 { turned or planed } less .05

In the length { of the bore, more or less .10 { from rear of base-ring or line to face of { the muzzle, more or less .25 { of the cascabel, from rear of base-ring to { the end, more or less .20 { of the reinforce, more or less .15

From the axis of trunnions to base-line, more or less .05

In the length of chamber, more or less .10

In the position of the axis { above axis of the bore .00 of the trunnions { below axis of the bore .20

In the length of trunnions, more or less .05

Diameter of trunnions, less 0.05

In the same gun, no variations to be tolerated in the position of the trunnions, or in their alignment.

In the vent { diameter more 0.025 { do. less .000

In lock-piece any dimensions {more .10 {less .00

Variation of position of exterior orifice of vent .05 Idem of interior do. do. .20

Depth of cavities { in the bore or vent .00 { on exterior surface of reinforces, { where turned or planed .10 { elsewhere, where turned or planed .25 { on trunnions, within one inch of rimbases .10 { on trunnions, elsewhere .25

Enlargement or indentation of bore by proof, not to exceed .02

The measures are to be taken by scales corresponding with the standard measures of the United States.

If two or more cavities should be near each other on the exterior, the gun may be rejected, though the cavities should be of less depth than tolerated in the table.

If the trunnions are placed within the limits of toleration, the preponderance must not vary more than 5 per cent., more or less, from that fixed in the contract.

POWDER-PROOF.

31. The proof-charges shall be as follows:

- + CALIBRE AND CLASS OF GUN. CHARGE PROJECTILE. WADS. NO. OF OF POWDER. FIRES. + - Shell-guns. Pounds. { 35 Shell 330 lbs. 3 XV-inch 43,000 lbs.{ 45 Shell 330 lbs. 3 { 55 Cored sh. 400 lbs. 3 XI-inch 16,000 lbs.{ 25 Solid shot Gromet 1 { 15 Shell 10 X-inch 12,500 lbs.{ 18 Solid shot Gromet 1 { 12 Shell 10 IX-inch 9,000 lbs.{ 15 Solid shot Gromet 1 { 10 Shell 10 8-inch of 63 cwt., or 7,000 lbs.{ 12 Shot Gromet 1 { 10 Shell 10 8-inch of 6,500 lbs.{ 10 Shot Gromet 1 8-inch of 55 cwt., or 6,000 lbs.{ 10 Shot 1 { 8 Shell 10 32-pdr. of 4,500 lbs. 8 Shot 10 - + Shot-guns. 130-pdr. of cwt., or 16,000 lbs. 30 1 Shot Gromet 10 64-pdr. of 106 cwt., or 12,000 lbs. 20 do. do. 10 32-pdr. of 57 cwt., or 6,400 lbs. 15 do. do. 10 32-pdr. of 51 cwt., or 5,700 lbs. 13 do. do. 10 32-pdr. of 42 cwt., or 4,700 lbs. 10 do. do. 10 32-pdr. of 33 cwt., or 3,600 lbs. 10 do. do. 10 32-pdr. of 27 cwt., or 3,000 lbs. 9 do. do. 10 + -

The cannon-powder for proof shall be of not less than 1,500 feet initial velocity, as determined by the gun-pendulum at the Ordnance Yard, Washington.

It shall be filled in service cylinders, and well settled.

For chambered pieces the increased charges should fill the chamber and necessary portion of the bore.

The projectiles shall be of full weight, and not below the mean gauge; the shells shall be filled with a mixture of sand and ashes, to bring them up to the proper weight of the filled shell.

Sabots for the shell and a gromet wad over the shot.

The gun should be fired on skids or a proving-carriage, to test the trunnions.

If five per cent. out of any lot offered for ordinary proof under a contract shall fail to sustain it, the whole may be rejected, as may be stipulated in the contract.

WATER-PROOF.

32. The pressure to be applied in the water-proof will be two atmospheres, or thirty pounds to the square inch.

The penetration of water in this proof through the metal of the piece, in any place, will cause the rejection of the gun; and if, on examination after the water-proof, there shall be any defects indicated by weeping or dampness in the bore, the gun shall be rejected.

The water-proof is alone to be depended on to detect minute clusters of cavities in the bore, which for this purpose should be perfectly dry, and examined by sunlight. All inspections, consequently, should take place in fair weather, and when the temperature is above the freezing-point.

MARKING GUNS.

33. Guns for the naval service, received by authority of the Bureau of Ordnance, are to be marked in the following manner, viz.:

On the cylinder, in the line of sight near the sight-mass, all accepted guns are to have stamped an anchor two inches long.

Drawings of these stamps will be furnished by the Bureau of Ordnance.

On the base ring or line, the initials of the foundry, the register number, and the weight of gun in pounds.

On the right trunnion, the calibre and year of fabrication.

On the left trunnion, the letter P. and the initials of the inspecting officer; all the above in one-inch letters.

On the upper jaw of the cascabel, the preponderance in pounds to be stamped lightly with half-inch figures.

On the end of the upper jaw, the cascabel block and head of the pin, the foundry number in quarter-inch figures.

The foundry number is also to be marked on the right rimbase.

Guns rejected for imperfections of any kind will have the letter C. stamped on the anchor, so as to partially obliterate it.

The founders are to be dissuaded from selling such guns to other parties, and required to break them up.

Guns rejected for such defects as render them dangerous to those who fire them, should be irreparably mutilated, with the consent of the founder.

EXTREME PROOF OF TRIAL-GUNS.

34. The extreme proof of guns intended for trial of metal, subject to such modifications by the Bureau as future experience may dictate, will be conducted as follows:

A suitable 'butt' shall be erected to arrest the flight of the projectiles used in proof, and to admit of their easy recovery, and a bomb-proof, readily accessible, for the protection of the firing party.

When practicable, the 'butt' should be made thick enough to allow the shot to just pass through, and be stopped by another beyond it, without penetrating the latter; this is, for XI-inch, about 12 feet.

With care, it is estimated that 130 shells may be fired 1,000 times, at the rate of one hundred rounds, per day.

After undergoing the ordinary proof established for its calibre and class, the gun selected for extreme proof shall be subjected to at least 1,000 rounds with service charges.

It may be fired from the skids, or suspended, as the Bureau may direct.

During the trial the gun shall be frequently and critically examined, inside and out, for cracks or defects, especially about the interior orifice of the vent, of which impressions are to be taken in wax at regular intervals, in the manner prescribed on page 16, or in such other manner as the Bureau may direct. If they show that the vent is corroded in furrows, and enlarged considerably in diameter at its junction with the bore, a permanent impression is to be taken in lead, to show the conical enlargement. The following manner, practised at the Experimental Battery at Washington, is recommended:

IMPLEMENTS REQUIRED.

35. 1. A soft wire about 0.07 in. in diameter, and 3 or 4 fathoms long.

2. A lever about twice the length of the bore, and about 3 inches in diameter, and shod to suit the curve of the bore nearly.

3. A small button of soft lead, judged to be of sufficient size to fill the vent at least one inch from the bore. This is to be pierced lengthwise to receive the wire.

TO TAKE THE IMPRESSION.

36. Shove the wire through the vent; let it pass along the bore and out at the muzzle; put it through the leaden button and tie a knot at the end. Draw the wire back through the vent until the leaden button is introduced firmly into the inner orifice.



Apply the lever, making its shoe bear on the button, and force it well in by repeated blows, the muzzle being the fulcrum. This done, disengage the button by pushing in the priming-wire.

In taking impressions of the vent and cracks, each button in turn is used as a pattern for moulding its successor, allowing for the progressive enlargement of the vent, or the cracks emanating from it. When the crack shows itself, the head of the button should be so enlarged as to include it.

These examinations should take place after every twenty fires, at least, and more frequently when any unusual enlargement of the vent or extension of cracks shall be developed, and indicate its speedy destruction.

Before each examination the bore of the gun is to be carefully washed and dried.

In recording the measurements of the bore in extreme proof and after service, distinguish between "indentation," which is the depression at the "seat of the shot," which is always below, and the "wear of the bore," which is generally above, and increase of bore, or "enlargement" from any other cause.

When from the appearance of the bore at the interior orifice of the vent, and especially when a crack or cracks appear to be extending rapidly, the vent so enlarged may be filled with melted tin, zinc, or Babbitt metal,—a tight-fitting sponge-head being pushed to the bottom of the chamber to close the interior orifice,—and the other vent be drilled through for the purpose of continuing the firing.

The precise time at which this is to be done will vary, according to circumstances; such as quality of metal, charge, and elevation.

The endurance of a smooth-bored gun with service charges may be surely predicted by observation of the progressive wear of the interior orifice of the vent.

There are certain general forms in which this enlargement takes place. They may be classed as triangular, lozenge, quadrilateral, star, circular, and elliptic. (See Plate.)

With the ordinary central vent, when subjected to a rapid, continuous fire, the enlargement usually takes the form of an isosceles triangle, the apex of one of the angles towards the muzzle, and the other two perpendicular to it.

With the lateral vent of the Dahlgren system it usually takes the lozenge form, the cracks extending from the opposite angles lengthwise of the bore.

With those rifled cannon in which the vent is bouched, the cracks appear around the bouching; and although the bouching preserves the vent, yet the formation of fissures around the enlarged orifice, when once commenced, causes a greater tendency to rupture. With the vent not bouched, the wear in rifled cannon is about double that of the smooth-bore.

So long as the wear of the vent is regular and without cracks, a mere enlargement is not indicative of danger; but when it reaches a diameter of four-tenths (.4) of an inch the vent should be closed and a new one opened.

A gun of large calibre should not in service be expected to endure more than 400 or 500 rounds before it will be necessary to open the new vent, which, however, will be of no advantage, unless the old one be closed at its interior orifice, on which the gases would otherwise continue to act as a wedge.

The first distinct appearance of the cracks, as shown by the button, is the proper limit.

After the gun bursts, make a sketch or draft showing lines of fracture, and reserve specimens to be sent to the Ordnance Yard at Washington for trial of density and tensile strength; and, if practicable, a photograph should be taken.



PREPARATION OF GUNS FOR SERVICE.

37. After the guns have been received at the Navy Yards it is necessary to adjust the sights, and, in the guns of the Dahlgren pattern, cut the screw hole in the cascabel.

CUTTING THE SCREW-HOLE.

38. The boring and screw-cutting machine is a convenient portable hand drill-press, the use of which is readily understood by any machinist.

The gun being carefully levelled, and the trunnions placed horizontal, the position of the centre of the screw-hole, which in the guns of the Dahlgren pattern is tangent to the radius of the breech, is marked on the neck of the cascabel with a centre punch.

The machine is placed on the cascabel, the boring shaft inserted in the hollow leading bar, and its movable centre placed on the mark. The instrument is then set vertical, by a spirit-level on the cogged driving-wheel, and the four pairs of set screws on the clamp-head embracing the cascabel.

The centre is then removed, and a drill inserted in the lower extremity of the boring-shaft, which, being held firmly by a shoulder and turned by a four-armed wrench, while pressed up to the metal by slowly turning the cogged driving-wheel, cuts the hole. This is successively enlarged, by two or more counterbits, to the size of the body of the screw.

The cutter is then inserted in the leading bar, and the thread cut.

ADJUSTMENT OF THE SIGHTS.

39. The bore having been thoroughly cleaned, the axis is levelled by a spirit-level; this may be very conveniently done by the aid of the levelling-bar. The axis of the trunnions is to be laid horizontal, either by placing a small level on the trunnions, or, as more exact, by using the trunnion-square. If the trunnion-square is used it will be proper to verify the position of the line of sight, which is frequently incorrectly placed at the foundries.

The breech-sight is then to be adjusted.

A brass head or tompion, fitted with a vertical arm, on which there is a ledge for a spirit-level, is then introduced into the bore, and the arm placed vertical by the spirit-level and a tangent screw.

The arm is pierced on its centre line with two holes—one at the height of the prescribed diameter of the muzzle, the other at a height equal to the proper distance of the bottom of the sight-notch from the axis of the bore. A waxed thread or fine wire, being stretched from the upper hole to the centre of the sight-notch, will coincide with the line of sight traced on the swell of the muzzle, the top of the reinforce sight-mass, and the base-line, if they are correctly placed. It will also be parallel to the axis of the bore if the adjustment of the breech-sight is exact, and the top of the reinforce-sight is made to coincide with it.

This is, however, seldom the case, and after the adjustment of the reinforce-sight it is necessary to verify it.

This is done by the levelling-bar—a square steel bar with parallel faces, somewhat longer than the distance between the sights, the rear end of which is bevelled at 60 deg. (the angle at which the sight is placed).

The outer end of this bar is placed on the reinforce-sight, which has been previously adjusted to the proper height, and the bevelled end in contact with the outer face of the sight-bar. The bar is then levelled by two screws placed near the inner end, and a spirit-level on its upper surface.

If then the bottom of the sight-notch coincides with the bottom of the bar, the line of sight is parallel to the axis; otherwise, the reinforce-sight or the sight-bar must be lowered until coincidence is obtained.

A centre line on the bar verifies the coincidence of the line of sight, and also the motion of the sight-bar in the vertical plane. The bevel verifies the angle of the bar; and the distance between the outer faces of the sight-notch and of the reinforce-sight, being also marked on the levelling-bar, verifies this adjustment.

Another method is sometimes and more advantageously used in adjusting the sights of guns which have not been turned.

Two iron or wooden disks are turned to the exact diameter of the bore, and placed on a rod two or three feet longer than the bore. One of the disks is placed near the bottom of the bore, the other just within the muzzle. On the part projecting beyond the muzzle there is a double square, each arm of which is divided into equal parts and traversed by a fine slit.

The square being set vertical by a spirit-level or plumb-line, and a waxed thread or wire stretched taut from the outer arm through the slit, cutting equal divisions on each, and passing through the centre of the slit, it is evident that a line of sight is obtained through the centre of metal and parallel to the axis of the bore.

This method has the advantage of adjusting the sights in any plane parallel to the axis, as in the case of the side-sights of rifled and other cannon.

ADJUSTMENT OF THE SIDE-SIGHTS.

40. The gun having been levelled, and the trunnions placed horizontal, a centre line is to be drawn on the top of the left (or right) rimbase.

The support for the sight is then to be fitted to the breech, at the distance from this line marked on the pattern-sight for its calibre, with the bottom of the sight-notch in the bar, exactly the height of the front sight (one inch) above the upper surface of the rimbase; the sight-bar perpendicular.

It is advisable to place a very thin sheet of rubber under the support, to prevent the heads of the screws from being jumped off by the vibration. The screws have the same thread as those for the present reinforce-sight.

After the breech-sight is adjusted, a parallel to the axis of the bore is to be drawn in the usual manner, and the front sight screwed in on the rimbase.

Some trifling adjustment may then be required, to bring the height of the top of the front sight and the bottom of the sight-notch parallel to the axis of the bore in both the horizontal and vertical planes.

PRESERVATION OF GUNS.

41. Guns received at Navy Yards are to be carefully placed on the ranges of masonry, capped with iron skids or bars. It is intended that these shall be so high that the guns may be rolled upon them without their trunnions touching the ground, and that the earth will not be beaten up against their muzzles by heavy rains.

42. The surface over which guns are to be stowed should be kept firm and clear of all vegetation, and for this purpose should be covered with cinders from the smiths' forges, or other substance unfavorable to or destructive of the growth of plants and grasses.

43. In stowing the guns they should be made to rest on one of the skids or bars, a little forward of the base-ring, the muzzle depressed, but not so much as to prevent the use of the sponge to clean out the gun; the axis of the trunnion of each to be inclined the same way, and just enough not to touch the adjoining gun; the vents to be upwards.

44. Before the stowage is finally made they should be carefully and thoroughly cleaned from rust and all improper coatings, and be lacquered internally and externally with such composition as may be directed by the Bureau. This should be applied, when practicable, when the guns are well warmed by the rays of the sun. The vents and all screw-holes are to be stopped with plugs made of soft wood or oakum dipped in tallow, after they have been protected by an application of beeswax dissolved in spirits of turpentine, or other composition that may be directed by the Bureau.

45. No tompions are to be put into the guns when they are stowed unless expressly directed by the Bureau; if so ordered, a score must be cut out from them on the lower side, half an inch wide and equally deep.

46. In lacquering guns care is to be taken to leave the distinguishing marks and numbers distinctly visible.

47. Shell-guns are always to be denominated by the diameter of the bore; shot-guns by the weight of their shot.

48. Guns of the same calibre and class, when it can be conveniently done, are to be stowed in the same tier or range, and those of each class belonging to or selected for any particular vessel kept together. Each tier or range of guns of a particular calibre or class is to be marked accordingly with paint on a sign-board, and the first gun of each class belonging to a vessel is to be marked with the name of the vessel.

49. The Officer on Ordnance duty will examine all the guns in the yard and on board vessels in ordinary, at least once in every two weeks, and take care that they are kept protected from rust or any other injury, and will report to the Bureau whenever any additional precautions or arrangements are required for their proper preservation, and which may not be furnished by the order of the Commandant of the Yard.

50. No cutting, boring, or chiselling of guns is to be done at any time without express authority from the Bureau.

51. No condemnation of guns or small arms belonging to the Navy is to be made, except upon surveys specially ordered, and confirmed by the Chief of the Bureau; nor of other articles which have been furnished under his authority, or by his direction, unless by surveys ordered or sanctioned by him.

52. When guns and their equipments are to be put on board vessels for their armament, the guns are to be carefully and thoroughly cleaned and examined, to see that they are in all respects in proper serviceable condition.

The vents should be examined with the vent-gauges and searchers, to see that they are clear from any substance which may obstruct the use of priming-wires and primers.

53. The carriages are also to be carefully examined, the trunnion-holes and arms of the axletrees cleaned, and saturated with boiled linseed oil, the cracks filled with putty, and rubbed smooth, and the trunnion-holes black-leaded. The iron work should be freed from rust, all screws be made to work easily, and be well cleaned and coated with proper composition.

54. The Ordnance Officers will see that the sights are properly fitted and marked for their proper guns. The greatest care should be taken that they are properly adjusted, as the efficiency of the ship depends on it, and it is difficult to detect or remedy any error after they are placed on board; that the beds and quoins are fitted and adjusted, and the quoins graduated to degrees or distances to correspond with those marked on the sight-bars. Porter's quoin is adopted for all carriages requiring quoins.

55. New guns are to have locks fitted to them before being put on board ship. Those having two lugs will have the one on the right fitted; the other is to be left solid.

56. When the guns are to be shipped for transportation merely, the same precautions are to be taken to guard them from injury as on shore, with the addition of a wad dipped into the composition which covers the bore, thrust into the muzzle, and connected with the tompion by a lanyard.

In the transportation of guns by rail—unboxed—the vents are to be plugged with soft wood, puttied over, and turned vent downwards on the trucks. All bronze howitzers transported by rail shall be boxed.

57. At the termination of a cruise the guns composing the battery of every vessel-of-war of the United States, shall be carefully examined by the Ordnance Officer of the Yard, and such others as may be directed, with the view to discover and report any injuries which they may have sustained in service, or any defects which may not have been developed in the original proof. In this examination the attention of the Inspecting Officers is to be directed to the following points, viz.:

Enlargement of the interior or exterior orifice of the vent.

Indentations or hollows produced by the shot balloting against the surface of the bore, or by the action of the gases.

Cuts or scratches in the bore, produced by fragments of broken or the roughness of imperfect shot.

Roughness or corrosion of the metal on the exterior, produced by neglect or exposure.

Similar injuries in the bore, or any enlargement of the bore, which is to be ascertained by measuring with the star-gauge, at every one-fourth (1/4) of an inch from the bottom of the cylindrical part to the seat of the shot, every inch from that point to the trunnion, thence every 5 inches to the muzzle, and the results recorded in the usual form, and reported to the Bureau, that they may be compared with those noted at the original inspection.

In rifled cannon, cracks or injuries produced by firing, or the rupture of shells, are to be sought for:—

Around and in rear of the vent bouching;

On the top of the bore, between the trunnions and reinforce band.

On the lower side of the bore, near the seat of the shot, at the junction of the lands and grooves.

Near the inside of the muzzle, caused by explosion of shells.

Care is to be taken that the distinguishing marks and numbers are always accurately noted, that the correct history of each gun may be preserved.

58. Before sailing, the Inspector of Ordnance will furnish the commander with a descriptive list of his battery, together with a statement of the number of times each gun on board has been fired, in the following form; a copy of which the commander shall transmit to the Bureau before sailing: this list shall be returned to the Inspector of the Yard to which she may return, with all additional firing noted opposite the number of each gun, certified "correct" by the commander.

In the list furnished by the Inspector, if the "number of fires" is estimated, it is to be entered in red ink (See Arts. 62-64), and so carried forward in the subsequent returns.

NAME OF VESSEL. STATION.

( ) ( ) -+ -+ + + -+ + CLASS MARKS ON BASE-RING. TRUNNIONS. PIVOT, OR WHERE NUMBER OF + -+ +BROADSIDE. RECEIVED. FIRES OF GUN. Reg. No. Weight. Foundry. Right. Left. TO DATE. -+ + -+ + + -+ + -+ + -+ + -+ + + -+ + -+ +



Forwarded by Commanding.

59. The Bureau directs that, whenever a gun is taken on board a vessel, the number of rounds which have been fired from it be ascertained by the Commander, a record made thereof, and forwarded with the descriptive list, in the above form, to the Bureau; and whenever a gun is landed or transferred to another vessel, a similar record is to be furnished the officer receiving it, which must be stated in the receipt for the gun, and a copy forwarded to the Bureau of Ordnance by the officer delivering the gun.

The Commander shall also transmit to the Bureau a quarterly return, according to the prescribed form (See Appendix B, No. X.) of all firing whether with or without projectiles, in action or otherwise; noting particularly the kind of shell, species of fuze, kind, charge, and name of maker of the powder used in the gun and shell. He shall take care to note also the number of premature explosions of shells, and the point at which they take place, with the supposed causes thereof.

60. The Inspector will also furnish the commander with a set of leaden impressions of the interior orifice of the vents of the guns, secured in a suitable box, that he may be able to compare the wear and gradual enlargement. These will be transferred with the guns to other ships or when landed.

61. The protracted firing to which the Navy cannon have been subjected, and to which they will continue to be liable, renders it necessary not to exceed the number of fires designated for each vent.

These must never exceed five hundred (500) fires for each vent.

In the IX-in., XI-in., and guns of similar form, the right vent is always bored through, and the left initiated sufficiently to give it direction.

When five hundred (500) rounds have been fired from the right vent, it is to be closed by filling it with molten zinc or lead, and the left vent is to be bored, which will require a skilful mechanic.

When the left vent has been fired five hundred (500) rounds, the gun is to be disused, as it will then have been fired one thousand (1,000) times.

It may happen, from some peculiarity in the nature of the iron, that the vent may be worn to its full extent before five hundred (500) rounds have been fired, in which case the vent is then to be closed, and the other vent opened.

The gun should be frequently and critically examined inside and out for cracks or defects, especially about the interior orifice of the vent, of which impressions should be taken after every ten shotted rounds in practice, and at the close of an action.

The instrument described on p. 16 is convenient, but by no means indispensable—any small spar, such as a boat's mast, or even the rammer handle with a curved piece of wood seized to the end, will, in expert hands, take an impression of the vent or crack equally well.

62. As the best indication of the amount of firing to which any smooth-bored gun has been exposed, when it is not otherwise known, is given by the enlargement of the vent, particular attention will be paid, in the reinspection of the guns, to this point. The standard gauge will be used to ascertain the general enlargement, and the searcher to detect defects which may have been developed in firing. Impressions are to be taken of the lower orifice of the vent with softened wax, and if they show that the vent is corroded in furrows and enlarged considerably in diameter at its junction with the bore, a permanent impression is to be taken in lead to show the conical enlargement. (See mode of taking impressions, Arts. 35 and 36.)

63. When the number of rounds fired is not known, an estimate may be made from an examination of the vent by cylindrical gauges differing from each other by .01 of an inch passed through it. If the number is estimated, it is to be entered in red ink.

64. In all the guns of the Dahlgren pattern the vents are (.2) two-tenths of an inch in diameter. In all other guns .22 of an inch exterior, .2 of an inch on the interior.

Observation of the wear of the vent in proof firing of smooth-bored guns gives the following as the average diameter of the vent, after the undermentioned number of fires:

No. of rounds 100 200 300 400 500 Diameter of vent .24 .26 .30 .35 .40

These, combined with examination of the interior orifice, will enable a very correct judgment to be formed of the probable number of fires sustained and duration of the gun.

The larger the calibre and the heavier the charge the more promptly the wear is manifested on the interior and exterior.

This enlargement does not extend very far from the lower orifice until the enlargement on the exterior has reached a diameter of .3 of an inch.

65. So long as the wear is regular, and the cracks, although numerous, do not exceed .5 of an inch in length, the indications are good. If the cracks are but few or diminish in number, running into each other and extending rapidly, it is a very unfavorable sign. In the rifle cannon (Parrott's) cracks athwart the bore either running into the bouching or in the rear of it are very unfavorable to the gun's endurance.

66. Whenever any premature explosions of shells take place within the gun or near the muzzle, a careful examination of the gun shall be made; and all the circumstances of the case, together with the opinions of the commander and officers in immediate charge as to the cause thereof, reported to the Bureau; taking care to state the kind of shell and species of fuze used; the mode of loading; whether the shell was lined or coated on the interior; kind, charge, and name of maker of the powder which was used in the gun and shell.

There is reason to believe that few failures of the Parrott rifles have occurred where the guns have not been previously, or at the time, injuriously strained by the explosion of shells within the bore.

67 Whenever a gun shall give away under fire, or an accident of any kind happen to one, the Bureau desires to be immediately informed of all the facts in relation thereto.

Particular attention should be paid to the following points:

1. The manner in which the gun was loaded, stating the charge and kind of powder used, and character and weight of projectiles.

2. The condition and appearance of the gun after it gave way, and what effect was produced on the carriage by the explosion.

3. What injuries, if any, occurred to the crew of the gun or vessel.

Sketches of the gun and fragments which remain should also be sent to the Ordnance Yard at Washington for trial of density and tensile strength, accompanied by the written statement in detail of the officers in immediate charge of the gun, and if practicable a photograph should be taken.

INSPECTION OF SHOT AND SHELLS.

RULES AND MEMORANDA FOR THE GOVERNMENT OF INSPECTORS.

68. All shot and shells for the naval service must be—

1st. Made from gray or mottled charcoal pig-iron.

2d. This iron most not be blasted with anthracite coal.

3d. It must be poured into sand moulds.

69. After being cast in this manner, the shot and shells must be—

1st. Spherical.

2d. Smooth on the surface.

3d. Free from the defects named in the following rules for the use of the inspecting instruments:

FOR SHOT.

70. INSPECTING INSTRUMENTS.—One large, small, and one medium ring gauge, and one cylinder-gauge for each calibre. The cylinder-gauge shall have the same diameter as the large gauge, made of cast iron, and three calibres in length. One hammer weighing two pounds, and having a flat face and a conical point; one searcher, of steel wire, with a handle; one pair of calipers and standard scale; one cold chisel; steel punches.

71. After having been well cleaned, each shot is placed upon a table, and examined to see that its surface is smooth, and that the metal is sound and free from seams, flaws, and blisters. If clusters of cavities or small holes appear on the surface, strike the point of the hammer into them, and ascertain their depth with the searcher. If the depth of the cavity exceeds 0.2 inch, the shot shall be rejected; it shall also be rejected if any attempt is made to conceal defects by plugging or filling holes in any mode whatever.

72. The shot must pass in every direction through the large gauge, and not at all through the small one; the calipers and scale will determine exactly the difference of diameters of the same projectile.

73. The ring and cylinder gauges shall be examined before each inspection, and when found to have enlarged 0.01 of an inch, must be laid aside and marked as unserviceable.

74. The shot are next to be passed through the cylinder-gauge, placed at an inclination of about two inches between the ends, and supported in such a manner as to be easily turned from time to time, to prevent its being worn in furrows. Shot which slide or stick in the cylinder shall be rejected; the latter must be pushed out from the lower end of the cylinder with a wooden rammer.



75. The next proof of shot is to drop a few taken indiscriminately from the lot under inspection from a height of twenty feet on a solid platform of iron, or roll them down an inclined plane of the same height against a mass of iron; after which they are again examined for defects of metal.

76. The average weight of shot shall be determined by weighing at least three parcels, of from 20 to 50 each, taken indiscriminately from the lot. As many of the lightest shall be weighed separately as the inspecting officer may deem necessary, and all found to fall below the least weight allowed in the annexed table of the dimensions of shot and shells shall be rejected. Shot made of charcoal iron will be stamped with a * or "burr" near the gate.

SHELLS.

77. Shells should be cast on a half-inch hollow spindle, to allow the gas to pass freely from the core; the fuze-hole would then be sufficiently large to admit the gauge for thickness before the shells leave the foundry.

78. INSPECTING INSTRUMENTS.—In addition to the instruments for shot, there will be required calipers with steel points for measuring the thickness of the shell at points on the great circle at right angles with the axis of the fuze-hole; gauges for the thickness at and opposite the fuze-hole; a conical flat steel gauge for the fuze-hole, marked at the point to which it should enter; a pair of strong hand-bellows, with a wooden plug to fit the fuze-hole and the nozzle air-tight. (See Plate.)

INSPECTION.

79. The surface of the shell and its exterior dimensions, form, weight, and strength, are to be examined and tested as in the case of shot, and subject to all the conditions there specified.

80. The greatest care is to be taken to remove every particle of sand or fragment of iron from the interior when they are about to be loaded for service. And the Inspectors of Ordnance at foundries or Navy Yards will satisfy themselves that this has been done before accepting or preparing them for service.

81. The shell is next struck with a hammer, to judge by the ring or sound whether it is free from cracks; and the exterior and interior diameters of the fuze-hole (which should be accurately reamed) are to be verified, and the soundness of the metal about the inside of the fuze-hole ascertained. To determine the thickness of the metal, three points, at least, on the great circle at right angles to the axis of the fuze-hole are to be measured; also one at the fuze-hole and one at the bottom. No shell shall be received which deviates more than one-tenth of an inch from the proper thickness in any part.

82. The shell is next placed in a tub of water, which should be deep enough to completely cover the shell. Air is then forced by the bellows into the shell. If there are any holes in it, air-bubbles will rise on the surface of the water, and the shell shall be rejected.

83. This occasionally occurs from the escape of air from porous spots which do not extend to the interior of the shells. In this case the action of the bellows produces no increase of bubbles, which cease rising as soon as the spots or cavities are filled with water. Porous spots are also detected by their absorbing water and drying slowly when exposed to the air, and shall likewise cause the rejection of the shell.

84. The Inspecting Officers will stamp the shell at one inch from the fuze-hole with their initials, also those of the foundry at which they are cast.

The Inspector or one of his assistants must be present when shot or shell are inspected; and the stamps and marks are always to be retained in the possession of the Inspector.

85. Rejected shells are to be mutilated by chipping a piece out at the fuze-hole.

86. If, upon the inspection of shot or shells, any of them should be found not to conform strictly to these instructions or to the requirements of the contract under which they are offered for reception, the Inspecting Officer is not to receive them; but if, in his opinion, the defects, taken in connection with the general character of the articles, will not impair their efficacy or render them unsafe or hazardous, he may refer to the Chief of the Bureau of Ordnance for his decision, forwarding to him minute and full information on the subject.

87. Shot and shells shall be delivered for inspection at the places specified in the contract, at the expense of the contractor; and those which are rejected shall be immediately removed, also at his expense.

TABLE OF SHOT AND SHELL GAUGES.

88. SHOT.

DIMENSIONS, WEIGHT. XV. XIII. XI. X. IX. 8. 32. (Cored.) - - - Diameter of large gauge for foundries. 14.83 12.83 10.83 9.83 8.83 7.88 6.28 Diameter of small gauge for foundries. 14.77 12.77 10.77 9.77 8.77 7.82 6.22 Mean of gauge for foundries. in. 14.80 12.80 10.80 9.80 8.80 7.85 6.25 Mean weight required of foundries. lbs. 400. 276. 166. 124. 90. 65. 32.5 Least weight allowed foundries. lbs. 64.5 32. Diameter of small gauges for service. {1st class in. 7.82 6.22 {2d class in. 7.80 6.20 - - -

89. SHELL.

DIMENSIONS, WEIGHT. XV. XIII. XI. X. IX. 8. 32. - - - - - Diameter of large gauge for foundries. 14.83 12.83 10.87 9.87 8.87 7.88 6.28 Diameter of small gauge for foundries. 14.77 12.77 10.83 9.83 8.83 7.82 6.22 Mean of gauge for foundries. in. 14.80 12.80 10.85 9.85 8.85 7.85 6.25 {Proper in. 2.85 2.37 2. 1.80 1.60 1.50 1.25 Thickness. {Greatest in. 2.95 2.47 2.10 1.90 1.70 1.60 1.35 {Least in. 2.75 2.27 1.90 1.70 1.50 1.40 1.15 Diameter of fuze-hole. {Proper and least .65 .65 .65 .65 .65 .65 .65 {Greatest .75 .75 .75 .75 .75 .75 .75 Diameter of large gauge for strapped. 14.93 12.93 10.93 9.93 8.98 7.93 6.33 Mean weight required for foundries. lbs. 330. 208. 127. 95. 68.50 50. 25. Least weight allowed foundries for any one. lbs. 126. 94. 67.50 49. 24.5 Weight of filled and sabotted. lbs. 352. 216.5 135.5 101.50 73.50 52.75 26.5 - - - - -

For gauges of boat-gun fixed ammunition, see Boat Armament of United States Navy, by Admiral Dahlgren, 2d edition, 1856.

90. SHRAPNEL.

DIMENSIONS, WEIGHT. XV. XI. X. IX. - + Mean of empty case. { Gauge in. 14.8 10.85 9.85 8.85 { Thickness in. 1.25 1. .87 .75 { Weight lbs. 178. 76. 57. 38. Balls { Number 1000. 625. 435. 350. { Diameter lbs. 1. .85 .85 .85 { Weight lbs. 140. 51. 33.5 27. Sulphur. lbs. 30. 10. 8.5 7. Bursting charge. oz. 10. 6. 4. 3. Weight complete. } Weight sabotted. } lbs. 358. 141. 101. 75. + -

DIMENSIONS, WEIGHT. 8. 32. 24 12 - - - -+ Mean of empty case. { Gauge in. 7.85 6.25 5.67 4.52 { Thickness in. .69 .60 .55 .45 { Weight lbs. 29. 15. 11. 6.5 Balls { Number 220. 235. lead 175. lead 80. lead { Diameter lbs. .85 .65 .65 .65 { Weight lbs. 17. 14. 10.5 4.75 Sulphur. lbs. 5. 2.25 1.5 .75 Bursting charge. oz. 2.5 1.25 450. 350. grs. grs. Weight complete. } Weight sabotted. } lbs. 52. 32. 24. 12. + - - - -

91. DIMENSIONS OF SABOTS AND STRAPS FOR SHELL AND SHRAPNEL.

DIMENSIONS, WEIGHT. XV. XIII. XI. X. IX. 8. 32. 24. 12. - - - - - - - - Thickness in. 5. 4.50 2.75 2.75 2.40 2. 1.50 1.90 1.50 Diameter {greatest in. 14.25 12.25 10.50 9.50 8.60 6.90 6. 5.7 4.60 {least in. 14.25 12.25 10.50 9.50 8.60 6.80 5.50 5.55 4.40 Depth of saucers in. 2.50 2.25 1.80 1.60 1.40 1.20 1. 1.50 1.30 Weights lbs. 8.90 5.50 2.70 2.40 1.85 .90 .50 .46 .22 Shell-straps {Length in. 25.75 22.5 17.25 17.25 14.75 13.25 10.25 7.625 6.375 {Width in. 1.25 1. .75 .75 .75 .75 .625 .50 .375 {Tin No. XXD XXD XXD XXD IX IX IC IC IC Tacks No. 20 16 12 12 8 8 8 4 4 - - - - - - - -

92. GRAPE.

RIFLE - DIMENSIONS, WEIGHT. XV. XI. X. IX. 8. 32. 24. 12. 20. 12. - - - - - - - -+ Weight of stand lbs. 34.75 26.10 20.4 15.7 8.75 Weight of balls lbs. 89.10 71.70 25.20 37.12 24.80 Number of balls 15. 15. 18. 18. 12. Diameter of balls in. 3.55 3.34 2.80 2.50 2.50 Weight complete lbs. 125.08 98.62 74.10 58.25 33.50 + - - - - - - - -