CHAPTER II._America's Munitions 1917-1918

GUN PRODUCTION.

The sole use of a gun is to throw a projectile. The earliest projectile

was a stone thrown by the hand and arm of man--either in an attack upon

an enemy or upon a beast that was being hunted for food. Both of these

uses of thrown projectiles persist to this day, and during all time,

from prehistoric days until now, every man who had a projectile to

throw was steadily seeking for a longer range and a heavier projectile.

The man who could throw the heaviest stone the longest distance was

the most powerfully armed. In the Biblical battle between David and

Goliath, the arm of David was strengthened and lengthened by a leather

sling of very simple construction. Much practice had given the young

shepherd muscular strength and direction, and his longer arm and

straighter aim gave him power to overcome his more heavily armed

adversary.

Later, machines were developed after the fashion of a crossbow mounted

upon a small wooden carriage which usually was a hollowed trough open

on top and upon which a heavy stone was laid. The thong of the crossbow

was drawn by a powerful screw operated by man power, and the crossbow

arrangement when released would throw a stone weighing many pounds

quite a distance over the walls of a besieged city or from such walls

into the camps and ranks of the besiegers. This again was an attempt by

mechanical means to develop and lengthen the stroke of the arm and the

weight of the projectile.

With the development of explosives, which was much earlier than

many people suppose, there came a still greater range and weight of

projectile thrown, although the first guns were composed of staves

of wood fitted together and hooped up like a long, slender barrel,

wound with wet rawhide in many folds, which, when dried, exerted a

compressive force upon the staves of the barrel exactly as do the steel

hoops of barrels used in ordinary commercial life to-day.

This, the first gun, sufficed for a long while until the age of iron

came. And then the same principle of gun construction was followed

as is seen in that historical gun, the "Mons Meg," in the castle at

Edinburgh. The barrel of that gun is made of square bars of iron,

placed lengthwise, and similar bars of iron were wrapped hot around the

staves to confine them in place and to give more resisting power than

was possible with the wooden staves and the rawhide hooping.

Thus, all during the age of iron, gun development went steadily

forward. Every military power was always striving by the aid of

its best engineers, designers, and manufacturers to get a stronger

gun, either with or without a heavier projectile, but in every case

striving for greater power. As a special development we find in March,

1918, the now famous long-range gun of the Germans, which was at that

time trained upon Paris, where it successfully delivered a shell

approximately 9 inches in diameter, punctually every 20 minutes for a

good part of each day until the gun was worn out. This occurred after a

comparatively small number of shots, probably not more than 75 in all.

The rapid wearing out was due to the immense demands of the long range

upon the material of the gun. The Germans in the shelling of Paris used

three of these long-range weapons and 183 shells are known to have

fallen in the city.

The Germans evidently calculated with great care and experience upon

the factors leading up to this famous long-range type of gun, which

had an effective shooting distance of approximately 75 miles, which

range, in the opinion of our experts, it is now quite easy for an

experienced designer and manufacturer to equal and excel at will. In

fact, one would hesitate to place a limit upon the length of range

that could be achieved by a gun that it is now possible to design and

build. In this connection it is interesting to note that the great

French ordnance works at Le Creusot in 1892 produced the first known

and well-authenticated long-range gun, which was constructed from the

design of a 12-inch gun, but bored down to throw a 6-inch projectile.

And instead of the usual 8 miles expected from the flight of a 6-inch

shell this early Creusot long-range gun gave a range of approximately

21 miles with a 6-inch projectile, using a 12-inch gun's powder charge.

Closely connected with the development of the gun itself, and a

necessary element of the gun's successful use, is the requirement that

the weapon itself be easily transported from point to point, where its

available range and capacity for throwing the projectile can be made

of maximum use. This requires a gun carriage which has within itself

various functions, the primary one being to establish the gun in the

desired position where it can be made most effective against the enemy.

Then, too, the gun carriage must have stability in order to withstand,

absorb, and care for the enormous recoil energies let loose by the

firing of the gun. It is obvious that the force which propels the

projectile forward is equal to the reacting force to the rear, and in

order to care for, absorb, and distribute to the earth this reacting

force to the rear the carriage must have within itself some very

peculiar and important properties. To this end there is provided what

is known as a "brake" which permits the gun, upon the moment of firing,

to slide backward bodily within the controlling apparatus mounted upon

a fixed carriage.

The sliding of the whole gun to the rear by means of the mechanism

of the brake is controlled, as to speed and time, by springs, by

compressed air, by compressed oil, etc., either all together or in

combinations of two or three of these agencies; so that the whole

recoil energy is absorbed and the rearward action of the gun brought to

rest in a fraction of a second and in but a very few inches of travel.

The strains are distributed from the recoil mechanism to the fixed

portion of the carriage that is necessarily anchored to the ground by

means of spades, which the recoil force of each shot sets more firmly

into the ground, so that the whole apparatus is thus steadily held in

place for successive shots.

In mobile artillery, again, rapid firing is a prime essential. The

75-millimeter gun of modern manufacture is capable of being fired at a

rate in excess of 20 shots a minute--that is, a shot every 3 seconds.

Rarely however, is a gun served as rapidly as this. The more usual rate

of fire is 6 shots a minute or 1 about each 10 seconds, and this rate

of fire can be maintained in the 75-millimeter gun with great accuracy

over a comparatively long period.

The larger guns are served at proportionately slower rates, until as

the calibers progress to the 14-inch rifles, which have been set up

upon railway mounts as well as on fixed emplacements for seacoast

defense, the rate of fire is reduced to one shot in three minutes for

railway mounts, and to one shot a minute for seacoast mounts, although

upon occasions a more rapid rate of fire can be reached.

Under rapid fire conditions, the gun becomes very hot, owing to the

heat generated by the combustion of the powder within the gun at

pressures as high as 35,000 pounds per square inch or more, which are

generated at the moment of fire. This heat is communicated through the

walls of the gun and taken off by the cooling properties of the air.

Nevertheless, the wall of the gun becomes so hot that it would scorch

or burn a hand laid upon it. The rapid fire and heating of the gun

lessens the effective life of the weapon, due to the fact that the hot

powder gases react more rapidly on hot metal than they do upon cold

metal; hence a gun will last many rounds longer if fired at a slow rate

than if fired at a rapid rate.

It may be helpful to keep in mind throughout that the sole purpose of

a gun is to fire a projectile, as was stated at the very beginning of

this chapter. All other operations connected with the life of a gun,

its manufacture, its transportation to the place where it is to be

used, its aiming, its loading and all its functions and operations are

bound up in the single purpose of actually firing the shot.

Consider now for a moment, the life of, let us say, one of the 14-inch

guns.

In the great steel mills it requires hundreds and perhaps thousands of

workmen to constitute the force necessary to handle the enormous masses

of steel through the various processes which finally result in the

finished gun.

From the first operation in the steel mill it requires perhaps as

long as 10 months to produce the gun ready for the first test. During

the 10 months of manufacture of one of these 14-inch rifles there has

been expended for the gun and its carriage approximately $200,000. Of

course, while it requires 10 months to make a final delivery of one

gun after its first operation is commenced, it should be remembered

that yet other guns are following in series and that in a well-equipped

ordnance factory two and perhaps three guns per month of this kind can

be turned out continuously, if required.

Remembering now that it requires 10 months to produce one such 14-inch

rifle and that its whole purpose is to fire a shot, consider now the

time required to fire this shot. As the primer is fired and the powder

charge ignited the projectile begins to move forward in the bore of

the gun at an increasingly rapid rate, so that by the time it emerges

from the muzzle and starts on its errand of death and destruction, it

has taken from a thirtieth to a fiftieth of a second in time, depending

upon certain conditions.

Assuming that a fiftieth of a second has been taken up and that the

life of a large high-pressure gun at a normal rate of firing is 150

shots, it is obvious then that in the actual firing of these 150 shots

only three seconds of time are consumed. Therefore, the active life of

the gun, which it has taken 10 months to build, is but three seconds

long in the actual performance of the function of throwing a shot.

However, after the gun has fired its life of 150 shots it is a

comparatively simple and inexpensive matter to bore out the worn-out

liner and insert a new liner, thus fitting the gun again for service,

with an expenditure of time and money much less than would be required

in the preparation of a new gun.

As the size of the powder charge decreases, a progressively longer life

of the walls of the bore of a gun is attained, so that we have had the

experience of a 75-millimeter gun firing 12,000 rounds without serious

effect upon the accuracy of fire. Large-caliber guns, such as 12-inch

howitzers, with the reduced powder charge required for the lower muzzle

velocities employed in howitzer attack, have retained their accuracy of

fire after 10,000 rounds.

From the fact that when in action guns are served with ammunition,

aimed, fired, and cared for by a crew of men carefully trained to

every motion involved in the successful use of the gun, it is most

essential that the design and the material shall be such, both as to

calculation in the design and as to manufacture in the material, as

will insure the maintenance of the morale of the crew that serves

the gun. Each man must be confident to the very last bit of fiber in

his make-up that his gun is the best gun in the world, that it will

behave properly, that it will protect him and his fellow soldiers who

are caring for the welfare of their country, that it will respond

accurately and well to every demand made upon it, that it will not

yield or burst, that it will not shoot wild, but that it will in every

respect give the result required in its operation.

To this end it has for generations been known that the requirements

of manufacture of ordnance material, particularly for the body of the

gun, are of the very highest order and call for the finest attainable

quality in material, workmanship, and design.

It is well known and admitted that the steel employed in the

manufacture of guns must be of the highest quality and of the finest

grade for its purpose. It requires the most expert knowledge of the

manufacture of steel to obtain this grade and quality. Until recently

this knowledge in America was confined to the Ordnance officers of

the Army and of the Navy and to a comparatively small number of

manufacturers--not more than four in all--and only two of these

manufacturers had provided the necessary equipment and appliances for

the manufacture of complete guns.

Until 1914 the number of guns whose manufacture was provided for in

this country as well as in the countries of Europe, excepting Germany,

was very small. It might be stated that the sum total of guns purchased

by the United States from the two factories mentioned did not exceed

an average of 55 guns a year in calibers of from 3-inch to 14-inch,

and that the stock of guns which by this low rate of increase of

manufacture had been provided for us was pitifully small with which to

enter a war of the magnitude of the one through which this country has

just passed.

The two factories in question not having been encouraged by large

purchases of ordnance material, as were similar industries in Germany,

were not capable of volume production when we entered the war. But

at the same time the gun bodies produced by these concerns at least

equaled in quality those built in any other country on earth; so that

while the big-gun-making art was in existence in this country and was

maintained as to quality, it was most insufficient as to the quantity

of the production available.

When the United States faced the war in April, 1917, arrangements

were at once entered into to obtain in the shortest space of time an

adequate supply of finished artillery of all calibers required by our

troops and to get this supply in time to meet our men as they should

set foot on the shores of France. Many thousands of forgings for guns,

and finished guns too, had been ordered by the allies of the few gun

makers in this country; and these makers were, at the time we got into

the conflict, fully occupied for at least a year ahead with orders from

the French and English ordnance departments. All of this production

was immediately useful and available for the combined armies of the

allies, and so it was allowed to go forward, the forgings preventing a

gap in the output of the finished articles from the British and French

arsenals which were then using the semifinished guns made in the old

factories in existence in this country in April, 1917.

Some idea of the volume of this production in this country will be

gained from the following table showing material supplied to the allies

between April, 1917, and the date of the signing of the armistice,

November 11, 1918.

Guns of calibers from 3-inch to 9.5-inch 1,102

furnished to the allies

Additional gun forgings furnished to the allies tubes 14,623

Shell and shell forgings furnished to the allies pieces 5,018,451

in this period

In supplying all of this material from our regular sources of

manufacture in this country to the finishing arsenals of the allies we

were but maintaining our position as a part of the general source of

supply. The plan of the French and British ordnance engineers at the

outbreak of the war in 1914 was to build their factories as quickly

and as extensively as could possibly be done. By the time the United

States entered the war all of these factories were in operation and

clamoring for raw material at a rate which was far in excess of that

which could be supplied by the home steel makers in Great Britain and

France. Consequently their incursions into the semifinished ordnance

material supplies in the United States were necessary. In sending these

large quantities of our own materials abroad, when we needed them

ourselves, we were distinctly adding to the rate and quantity of the

supply of finished ordnance for the use of our own Army in the field

as well as being at the same time of inestimable value to the allies.

This was because the French and British had agreed to supply our first

armies with finished fighting weapons while we were giving them the raw

materials which they needed so badly.

The four gunmakers in America meanwhile were being expanded into a

total of 19 makers. All of these 19 factories during the month of

October, 1918, were practically in full operation. Many of them were

producing big guns at a faster rate than that for which the plants

had been designed. In the month of October, 1918, with 3 of the 19

factories yet to have their machine-tool equipment completed, there

were produced 2,031 sets of gun forgings between the calibers of

3-inch and 9.5-inch, which is at the rate of upward of 24,000 guns

a year. This figure, of course, does not indicate anything of the

gun-finishing capacity of the country; yet this expansion may be

contrasted to the fact that our supply of finished guns prior to 1917

amounted only to 55 weapons a year.

_Monthly production of finished cannon, ranging in size from 75

millimeters to 240 millimeters, at the various machining and

assembling plants._[9]

------------------------+------+------------------------------------------

| 1917 | 1918

Caliber. +------+------+------+------+------+------+-------

| Dec. | Jan. | Feb. | Mar. | Apr. | May. | June.

+------+------+------+------+------+------+-------

75-millimeter | 5 | 45 | 48 | 52 | 74 | 127 | 169

3-inch antiaircraft | 3 | 16 | 24 | 16 | 2 | | 11

4.7-inch | | | | | | | 6

155-millimeter howitzer | | | 3 | 10 | 16 | 28 | 75

8-inch howitzer | | | | 34 | 38 | 8 |

+------+------+------+------+------+------+-------

Total | 8 | 61 | 75 | 112 | 130 | 163 | 261

========================+======+======+======+======+======+======+=======

| 1918 |

Caliber. +------+------+------+------+------+------| Total

| July.| Aug. | Sept.| Oct. | Nov. | Dec. |

------------------------+------+------+------+------+------+------+-------

75-millimeter | 142 | 204 | 199 | 214 | 320 | 214 | 1,813

3-inch antiaircraft | 10 | 11 | 22 | 50 | 34 | 31 | 230

4.7-inch | 8 | 15 | 29 | 71 | 50 | 39 | 218

155-millimeter howitzer | 110 | 248 | 206 | 350 | 231 | 179 | 1,456

155-millimeter gun | 2 | | 14 | 51 | 22 | 40 | 129

8-inch howitzer | | 28 | 22 | 33 | 14 | 14 | 191

240-millimeter howitzer | | 1 | | | 1 | | 2

+------+------+------+------+------+------+-------

Total | 272 | 507 | 492 | 769 | 672 | 517 | 4,039

------------------------+------+------+------+------+------+------+-------

[9] Carriages, recuperators, and sights had to be added to these cannon

to make them complete units ready for service.

_Monthly production of cannon forgings._

------------------------+------+------------------------------------------

| 1917 | 1918

Caliber. +------+------+------+------+------+------+-------

| Dec. | Jan. | Feb. | Mar. | Apr. | May. | June.

------------------------+------+------+------+------+------+------+-------

75-millimeter | 4 | 13 | 73 | 62 | 79 | 239 | 376

3-inch antiaircraft | | | 6 | 7 | 5 | 4 | 12

4.7-inch gun | | | 9 | 10 | 8 | 28 |

155-millimeter howitzer | 2 | 13 | 26 | 61 | 44 | 146 | 133

155-millimeter gun | | | | | 1 | 15 | 4

8-inch howitzer | | | | 34 | 38 | 8 |

+------+------+------+------+------+------+-------

Total | 6 | 26 | 114 | 174 | 175 | 440 | 525

========================+======+======+======+======+======+======+=======

| 1918 |

Caliber. +------+------+------+------+------+------| Total

| July.| Aug. | Sept.| Oct. | Nov. | Dec. |

------------------------+------+------+------+------+------+------+-------

75-millimeter | 574 | 678 | 754 |1,385 | 674 | 310 | 5,221

3-inch antiaircraft | 10 | 6 | 49 | 163 | 124 | 18 | 404

4.7-inch gun | 70 | 100 | 84 | 35 | 25 | 53 | 422

155-millimeter howitzer | 176 | 204 | 273 | 279 | 276 | 62 | 1,695

155-millimeter gun | 42 | 28 | 56 | 105 | 79 | 24 | 354

8-inch howitzer | | 28 | 22 | 33 | 14 | 14 | 191

240-millimeter howitzer | | 30 | 21 | 31 | 22 | 49 | 153

+------+------+------+------+------+------+-------

Total | 872 |1,074 |1,259 |2,031 |1,214 | 530 | 8,440

------------------------+------+------+------+------+------+------+-------

Our chain of gun factories, that were making this remarkable production,

were built as follows:

One at the Watertown Arsenal, Watertown, Mass., near Boston, for

the manufacture of rough machined gun forgings of the larger mobile

calibers. This factory was entirely built and equipped on Government

land with Government money and is splendidly able to produce rough

machined gun forgings of the highest quality at the rate of two sets a

day for the 155-millimeter G. P. F. rifles, and one set a day of the

240-millimeter howitzers.

At Watervliet Arsenal, Watervliet, N. Y., large extensions were made

to the existing plant that had always been the Army's prime reliance

for the finishing and the assembly of guns of all calibers, including

the very largest. This plant was extended to manufacture complete

four of the 240-millimeter howitzers each day, and two a day of the

155-millimeter G. P. F. guns.

At Bridgeport, Conn., there was constructed a complete new factory by

the Bullard Engineering Works for the United States to turn out four

155-millimeter G. P. F. guns a day.

At Philadelphia, the Tacony Ordnance Corporation, as agents for the

Government, erected complete a new factory officered and manned by

experts well-trained and experienced in the difficult art of the

manufacture of steel and gun forgings. On October 11, 1917, the grounds

for this great undertaking had been merely staked out for the outline

of the buildings. Seven months later, on May 15, 1918, the entire

group of buildings, comprising a complete steel works from making the

steel to the final completion of 155-millimeter gun forgings, was

entirely erected at a cost of about $3,000,000. This difficult and

rapid building operation was carried through successfully during the

extraordinarily severe winter of 1917-18. On June 29, 1918, the first

carload of gun forgings was accepted and shipped from this plant, so

we have the marvelous enterprise of building a complete steel works

from the bare ground forward to the shipment of its first forgings in a

total elapsed time of only eight and one-half months.

At another, the works of the Midvale Steel Co. in Philadelphia, large

extensions were made to enable some of the larger guns to be produced,

to be finished later at the Watervliet Arsenal.

At the Bethlehem Steel Co.'s plant, Bethlehem, Pa., as early as May,

1917, orders were placed and appropriations allotted for expansions

to this enterprise to enable a rapid output of a larger number of gun

forgings and finished guns.

Large extensions were made at the works of the Standard Steel Works

Co., Burnham, Pa., to increase their existing forging and heat treating

facilities, so that at this plant two sets of 155-millimeter howitzers

and one set of 155-millimeter gun forgings were produced each day.

At Pittsburgh, Pa., the plants of the Heppenstall Forge & Knife Co. and

the Edgewater Steel Co. were extended so as to provide for the daily

production at the first plant of forgings for one 3-inch antiaircraft

gun and one 4.7-inch gun, and at the second plant of forgings for one

155-millimeter G. P. F. gun and one 240-millimeter howitzer per day.

At Columbus, Ohio, the Buckeye Steel & Castings Co. in combination with

the works of the Symington-Anderson Co. at Rochester, N. Y., had their

facilities extended to provide for the manufacture each day of six sets

of forgings for the 75-millimeter guns.

At the Symington-Anderson Co. in Rochester, N. Y., there was provided

a finishing plant for the 75-millimeter gun with a capacity of 15

finished guns per day.

At Erie, Pa., one of the most remarkable achievements in rapid

construction and successful mechanical operation was performed by

the erection of a plant that was commenced in July, 1917, and out of

which the first production was shipped to the Aberdeen Proving Grounds

in February, 1918. The American Brake Shoe & Foundry Co. built and

operated this plant as agents for the Ordnance Department, and much

credit is due them for their energy and organizing capacity.

It is doubtful if history records any similar enterprise in which guns

were turned out in a plant seven months from the date of beginning the

erection of the factory. This plant was laid out to manufacture 10

of the 155-millimeter Schneider-type howitzers a day, and before the

signing of the armistice it had more than fulfilled every expectation

by regularly turning out up to 15 howitzers a day, or 90 a week.

At Detroit, Mich., the Chalkis Manufacturing Co. adapted an existing

plant, and additional facilities were erected for the manufacture of

three of the 3-inch antiaircraft guns each day.

At Madison, Wis., the Northwestern Ordnance Co. erected for the United

States an entire new factory, beautifully equipped for the manufacture

of four guns a day of the 4.7-inch model.

At Milwaukee, Wis., the Wisconsin Gun Co. put up for the Government an

entirely new works capable of finishing six 75-millimeter guns each

day. The plants at both Milwaukee and Madison acquitted themselves very

well and gave us guns of the highest quality.

At Chicago, the Illinois Steel Co. expanded existing facilities to

produce more of the necessary electric furnace steel, which was forged

into guns at several works producing gun forgings, both for the Army

and Navy.

At Indiana Harbor, Ind., the works of the Standard Forgings Co., whose

sole business had been the volume production of forgings with steam

hammers and hydraulic presses, were expanded to the enormous degree

of producing each day 10 sets of gun forgings for the 155-millimeter

howitzer and 25 sets a day for the 75-millimeter gun. It should be

stated that this was a triumph of organizing ability and that this

factory was one of our main reliances for these guns.

At Gary, Ind., the American Bridge Co. created what is perhaps the

finest gun-forging plant in the world, comprising four presses from

1,000 tons to 3,000 tons forging capacity and all the other necessary

apparatus for the production each day of two sets of 155-millimeter G.

P. F. guns and the equivalent of one and one-half sets a day of the

240-millimeter howitzers.

At Baltimore, Md., the plant of the Hess Steel Corporation was enlarged

from its peace-time capacity and caused to produce at three times its

normal rate the special steels required for gun manufacture.

It will become evident that the collection of machinery, buildings,

and equipment necessary to produce these guns in the short space

of time required and at the rate of production stipulated, was an

enormous task in itself. It required the production of vast quantities

of raw materials and the congregating in one place of large numbers

of men capable of undertaking the exceedingly intricate mechanical

processes of manufacture. The success of this plan and its carrying

out is due largely to the loyalty of the manufacturers who unselfishly

came forward early in 1917 and agreed at the request of the Ordnance

Department to turn over their plants, lock, stock, and barrel, to

the requirements of the department; agreed also to undertake the

manufacture of products totally unfamiliar to them; agreed likewise to

lend all of their organizing ability and great material resources to

the success of the plants which the United States found necessary to

build in the creation of a new art, in new locations and in an extent

theretofore undreamed of.

THE MAKING OF A BIG GUN.

Steel, of course, and steel in some of its finest forms is the basis

of gun manufacture. The word "steel" for the purpose of producing guns

means much more than is ordinarily carried by the word in its everyday

and most commonly accepted use. Only steel of the very highest quality

is suitable for gun manufacture, as was indicated previously when

attention was directed to the complete reliance which the operating

crews must place in their guns and the severity of the uses to which

the big guns are put.

Let us take a hasty trip through a big gun plant, watching the

processes through which is finally evolved from the raw materials one

of our hardy and efficient big guns.

Entering an open-hearth furnace building at one of our big gun plants,

we find two large furnaces in which the raw materials are charged.

Each of these furnaces is 75 feet long and 15 feet wide, and in them

in a shallow bath or pool lies the molten steel. The pool is about 33

feet long by 12 feet wide and approximately 2½ feet deep. This pool, or

"bath" as it is termed, weighs approximately 60 tons and is composed of

pig iron and well-selected scrap steel from previous operations.

The furnace is at all times during the operation of melting these raw

materials in the bath kept at such a high temperature that the eye may

not look within at the molten mass without being protected with blue

glass or smoked glass, exactly as when looking at the noonday sun. The

eye can see nothing in the atmosphere of the bath in which the steel is

being melted and refined because the temperature is so exceedingly high

that it gives a light as white as that of the sun.

After 12 or 15 hours of refining treatment in this furnace the metal

is tested, analyzed in the chemical laboratory, and, if found to be

refined to the proper degree, it is allowed to flow out of the furnace

on the opposite side from that through which it entered. Flowing out

of the furnace the entire charge of 60 tons finds its way into a huge

ladle which is suspended from a traveling crane capable of safely

carrying this great weight.

The ladle is then transferred by the crane to a heavy cast-iron mold

which is built so as to contain as much of the 60 tons of molten metal

as is required for the particular gun forging under manufacture.

The mold, which we have before us now on our imaginary trip through the

gun plant, will provide an "ingot" from the molten metal that will be

40 inches in diameter and 100 inches high. On top of this ingot is a

brick-lined so-called "sinkhead." This sinkhead is that portion of the

molten metal that has been allowed to cool more slowly in the brick

lining than the ingot does in the cast-iron mold proper. The ingot with

the sinkhead will weigh approximately 60,000 pounds.

This sinkhead is to insure greater solidity to the portion of the ingot

which is used for the gun forging. Only that part of the ingot below

the sinkhead enters the forging. The sinkhead itself is cut off while

hot under the press in a subsequent operation and afterwards remelted.

Next the ingot is placed under a 2,000-ton forging press which handles

ingots up to 45 inches in diameter. There it is forged into a square

shape after coming from the mold in an octagonal form. Previous to its

being put under this press, however, a careful chemical analysis has

been made of the ingot to determine that it is satisfactory for gun

purposes, and then before being put under the press the whole ingot is

heated in the charge chamber and fired either by a gas or oil flame.

[Illustration: VIEW OF LADLE, CONTAINING 60 TONS OF MOLTEN STEEL

SUSPENDED FROM A TRAVELING CRANE.

The ladle is receiving metal from the furnace and the crane is

conveying the ladle to the mold.]

[Illustration: MOLTEN STEEL BEING POURED FROM LADLE INTO MOLD, WHICH IS

OF HEAVY CAST-IRON CONSTRUCTION, AT THE TACONY ORDNANCE CORPORATION.

Arrow points from letter A to a completed ingot from a mold.

The brick-lined sink head is a part of the mold and is to

insure greater solidity to the portion of the ingot which is

used for the gun forging; only the part below the sink head

entering the forging, the sink head itself being cut off hot

under the press in a subsequent operation.]

[Illustration: VIEW OF INGOT MOLD.]

[Illustration: A 2,000-TON FORGING PRESS AT THE TACONY ORDNANCE

CORPORATION PLANT.

This press can forge ingots up to 45 inches in diameter. The

ingot under the press is shown in a partly forged state. Note

that the original octagonal shape of the ingot as it came from

the mold has been forged down to a square shape and later will

be forged into a round shape. After coming from the mold, the

ingot has been subjected to a careful chemical analysis to

determine its fitness for use as a gun barrel.]

[Illustration: A 9,000 TON HYDRAULIC FORGING PRESS IN THE PLANT OF THE

MIDVALE STEEL CO.

This press is needed for such large caliber guns as the 14-inch and

16-inch guns. The piece of forging under the press is armor plate and

not a gun forging.]

[Illustration: THREE TUBES OF THE 155-MILLIMETER GUNS SUSPENDED AT

FURNACE.

Three tubes of the 155-millimeter guns suspended at furnace

ready for heating and quenching to give them the necessary

combination of hardness and toughness. The door of the furnace

is open. The tubes remain in this furnace for perhaps eight

hours at a temperature of 1,500° Fahrenheit or until a bright

yellow color, uniform in every part.]

[Illustration:

A TUBE FOR A 12-INCH GUN JUST OUT OF THE FURNACE, WHERE IT WAS

TEMPERED AT WHITE HEAT AND IS NOW READY FOR QUENCHING IN THE

PLANT OF THE MIDVALE STEEL CO.

The gun tube is 41 feet long.]

[Illustration: TUBE OF A 155-MILLIMETER GUN BEING TURNED, PRIOR TO

BORING, AT THE TACONY ORDNANCE CORPORATION PLANT.]

[Illustration: TUBE OF A 155-MILLIMETER GUN IN A LATHE BEING BORED.

The ingot out of which this tube was made, came from the mold

in an octagonal shape and later was forged into a square

shape and finally made round. It now, too, has the hole bored

partially into it. Through this hole, ultimately, will pass the

projectile.]

The forging press used for the larger caliber guns, such as 14-inch and

16-inch, is of a 9,000-ton weight capacity.

After the ingot forging has been reduced from squareness to a

cylindrical shape under the press, it is allowed to cool, then taken

to the machine shop, where it is turned and the hole through which the

projectile ultimately will pass is bored into it. This hole is somewhat

smaller than the diameter of the projectile, because in the finishing

operation, when the gun is assembled finally and put together, the hole

must be within one-one-thousandth of an inch of the diameter required,

which is all the tolerance that is allowed from the accuracy to which

the projectiles are brought. Otherwise the accuracy of the gun in

firing would be injured and the reliability of its aim would not be

satisfactory.

During all of these operations with the ingot, the steel is largely

in the soft condition in which it left the forging press. As is well

known, steel is capable of taking many degrees of "temper." Temper

is an old term that no longer is quite descriptive of the condition

desired or obtained, but it is sufficiently expressive of the condition

desired for the purposes here. This condition is one of a certain

degree of hardness--greater than that ordinarily carried by the soft

steel--combined with the greatest obtainable degree of toughness. This

combination of hardness and toughness produced to the proper degree

resists the explosive power of the powder and also causes the wear on

the gun in firing to be diminished and made as slight as possible.

To effect this combination of hardness and toughness it is necessary to

take the bored and turned tubes of the guns and suspend them by means

of a specially made apparatus in a furnace where they are heated for a

period of perhaps eight hours to a temperature of approximately 1,500°

F. or a bright-yellow color, uniform in every part of the piece.

After being subjected to this treatment for the time mentioned, the

tube is then conducted by means of a traveling crane apparatus to a

tank of warm water in which it is dipped and the heat rapidly taken

from it down to a point of practically atmospheric temperature. This

"quench" as it is called, produces the required degree of hardness

called for by the ordnance officers' design; but the piece has not yet

got the required degree of toughness. This toughness is now imparted

to the hard piece by heating it once more in another furnace to a

temperature of approximately 1,100° F., or a warm rosy red, for a

period of perhaps 14 hours. From this temperature, the piece is allowed

to cool naturally and slowly to the atmospheric temperature.

The ordnance inspectors at this point determine whether the piece has

the required properties in a sufficient degree, by cutting from the

tube a piece 5 inches long and ½ inch in diameter. The ends of this

piece are threaded suitably for gripping in a machine. The piece is

then pulled until the half-inch stem breaks. The machine registers

the amount of force required to break this piece and this gives the

ordnance engineer his test as to the degree of hardness and toughness

to which the piece has been brought by the heat treatment processes

just described.

A satisfactory physical condition having been determined by pulling

and breaking the test pieces described, the whole forging is sent to

the finishing shop where it is machined to a mirror polish on all

its surfaces. The diameters are accurately measured and the forgings

assembled into the shape of a finished gun.

In this process there is required a different kind of care and

accuracy. Up until this time the care has been to provide a metal of

proper consistency and quality. From this point forward the manufacture

of a gun requires the machining and fitting of this metal into a shape

and form so accurate that the full strength of the gun and the best

accuracy of fire may be attained.

To explain how and why hoops are placed upon the gun tubing and how

the various hoops are shrunk from the outside diameter of the gun will

require a few lines.

Cannon are made of concentric cylinders shrunk one upon another. The

object of this method of construction is twofold. The distinctly

practical object is the attainment throughout the wall of each cylinder

of the soundness and uniformity of metal which is more certainly to be

had in thin pieces than in thick ones; the other object is more closely

connected with the theory of gun construction.

When a hollow cylinder is subjected to an interior pressure the walls

of the cylinder are not uniformly strained throughout their thickness,

but the layer at the bore is much more severely strained than that at

the outside. This can be readily seen if we consider a cylinder of

rubber, for example, with a bore of 1 inch and an exterior diameter

of 3 inches, which are about the proportions of many guns. If we put

an interior air pressure on the cylinder until we expand the bore to

2 inches, the exterior diameter will not thereby be increased 1 inch.

But supposing that it were increased as much as the bore, that is, 1

inch, we would have the diameter, and therefore the circumference, of

the bore increased 100 per cent, and the circumference of the exterior

increased 33-1/3 per cent. That is, the layer at the bore would be

strained three times as much as that at the exterior, and the interior

layer would commence to tear before that at the exterior would reach

anything like its limit of strength. The whole wall of the cylinder

therefore would not be contributing its full strength toward resisting

the interior pressure, and there would be a waste of material as well

as a loss of strength. Let us now consider, instead of our simple

cylinder, a built-up cylinder composed of two concentric ones, the

inner one of a bore originally a little greater than 1 inch, and

the outer one of exterior diameter a little less than three inches,

originally; so that when the outer one is pressed over the inner one

(its inner diameter being originally too small for it to go over the

inner one without stretching) the bore of the inner one is brought to

1 inch, and the exterior of the outer one to 3 inches. We now have a

cylinder of the same dimensions as our simple one, but in a different

state; the layers of the inner one being compressed and those of the

outer one extended.

If now we commence to put air pressure on the bore, we can put on a

certain amount before we wipe out the compression of the inner layer,

and bring it to a neutral state, and thereafter can go on putting on

more pressure until we stretch the inner layer 100 per cent beyond the

neutral state, as before; which would take just as much additional

pressure as the total pressure which we employed with our simple

cylinder. We have therefore gained all that pressure which is necessary

to bring the inner layer of our built-up cylinder from its state of

compression to the neutral state. If we have so proportioned the

diameter of junction of our inner and outer cylinders and so gauged

the amount of stretching required to get the outer one over the inner

one that we have not in the process caused any of the layers of the

outer one to be overstrained, the gain has been a real one, attained by

causing the layers of the outer cylinder to make a better contribution

of strength toward resisting the interior pressure. This is the theory

of the built-up gun.

The number of cylinders employed generally increases, up to a certain

limit, with the size of the gun, practical considerations governing;

and the "shrinkage," or amount by which the inner diameter of the outer

cylinder is less than the outer diameter of the one which it is to be

shrunk over, is a matter of nice calculation. Roughly speaking, it is

about one and one half one-thousandths of an inch for each inch of

diameter, varying with the position of the cylinder in the gun; and its

accurate attainment, throughout the length of the cylinder of a large

gun, is a delicate matter of the gun-maker's art and the machinist's

skill.

The method of assembly is to have the cold tube set upright and

prepared for a circulation of water within the bore of the tube to

keep it cool. Then the hoop, whose inside diameter is smaller than the

outside diameter of the tube on which it is to be shrunk, is measured

and carefully heated to a temperature of approximately 450° F., or just

about the temperature of a good oven for baking or roasting. This mild

temperature so expands the material in the hoop that the difference of

diameter is overcome and the hot hoop is expanded to a larger inside

diameter than the outside diameter of the cold tube on which the hoop

is to be placed. Next the hot, expanded hoop is placed in position

around the breech end of the tube, and slowly and carefully cooled,

so that in contracting from the high temperature to the low ordinary

temperature, the hoop shrinks toward its original diameter and thus

exerts an inclosing pressure or compressive strain upon the breech end

of the tube.

Now when the gun is fired the tube tends to expand under the pressure

and this expansion is resisted, first by the compressive force exerted

by the shrunken hoop and later by the hoop itself, so that the built-up

system is stronger and better able to resist the explosive charge of

the burning powder than would be the case if the gun were made in one

piece and of the same thickness of metal.

This brief explanation will show why so many pieces are provided for

the manufacture of the finished gun and the reason for the large number

of machine tools and machining operations necessary in order to carry

forward the manufacture of the finished article. Sometimes one or more

of the outer cylinders are replaced by layers of wire, wound under

tension.

Both our 4.7-inch gun, model 1906, with which our troops have been

equipped for a long time and which throws a projectile weighing 45

pounds a distance of about 6 miles, and the French 75-millimeter

(2.95-inch) gun, successfully used by the French since 1897, were

designed to be drawn by horses, and the guns are best used when drawn

by teams of 6 or 8 horses. As the horse has a sustained pulling power

of only 650 pounds, it is obvious that the weight to be drawn by the

team of 6 horses must not be more than 3,900 pounds. So there is

every incentive for making mobile artillery of this kind as light as

possible, consistent with the strength required for the work to be

done. Thus the pulling power of the horse coupled with his speed has

been the limiting factor in the design and weight of mobile field

artillery.

As one of our foremost United States ordnance engineers once said,

"the limited power of the horse is what has governed the weight of our

artillery," and that "if Divine Providence had given the horse the

speed of the deer and the power of the elephant, we might have had a

far wider and more effective range for our mobile artillery."

[Illustration: A SECTION OF THE MIDVALE STEEL CO. PLANT, SHOWING TYPES

OF 6-INCH, 7-INCH, AND 8-INCH, NICKEL-STEEL, BREECH-LOADING RIFLES.]

[Illustration: THREE FINISHED 8-INCH RIFLES, 45 CALIBERS, SET UP ON

TURRET MOUNTS IN THE PLANT OF THE MIDVALE STEEL CO. WHERE THEY WERE

MADE.

In the foreground are three large gun tubes partially

completed. This company started the manufacture of the first

piece of ordnance material in America in 1880.]

One of the answers of the United States ordnance engineers to this

problem, as developed in the recent war, has been the production of

a tractor to replace the horse, and this tractor has the speed of

the deer and the power of the elephant. The most powerful tractors

are mounted on track-laying devices and are colloquially known as

caterpillars. One of these powerful caterpillars, on which is mounted

an 8-inch howitzer with a range of 6 miles, which is manned and

operated by only two men, and which can go up hill and down hill, over

broken brushwood, trees, etc., was recently given a severe test at the

Aberdeen Proving Grounds. Here it was sent through a dense wood in

which it bumped square into a live locust tree that was 17 inches in

diameter at the bottom. This tree, almost the tallest in the wood, was

prostrated by the attack of the tractor, which rode over it and then

emerged from the wood, took up its position, and fired its shot almost

in as short a time as that which it takes to tell of the deed. Truly

the power of the elephant and the speed of the deer has been brought to

the aid of the ordnance engineer for any future warlike operations.

The number of workmen employed in gun production at once in this

country totaled 21,329, and fully that many more are estimated to have

been employed in the manufacture of gun carriages and fire-control

instruments. Consequently in turning out the complete big guns there

were fully 42,000 workmen engaged by the month of October, 1918.

Furthermore, these men became so skilled in their work that it may be

said that the difficult art of gun making has become firmly established

in this country and that the United States may now and at any time in

the near future rely on this trained body of artisans for the finest

kind of gun-metal manufacture.

PRODUCTION OF CANNON FORGINGS.

_Production of cannon forgings during the war at the various

plants._

------------------+------------------+-----+-------------------------------

Caliber. | Contractor. |1917 | 1918

| +-----+----+-----+----+----+----+-----

| |Dec. |Jan.|Feb. |Mar.|Apr.|May.|June.

------------------+------------------+-----+----+-----+----+----+----+-----

75-mm. field gun, |Bethlehem Steel | 2| 1| 32| 14| 13| 3| 75

|Pa. | | | | | | |

| | | | | | | |

|Standard Forgings | 1| 5| 11| 10| 19| 5| 67

| | | | | | | |

|Buckeye Steel | | | | | | 154|

| | | | | | | |

75-mm. field gun, | do. | | | | | | 44| 162

| | | | | | | |

|Standard Forgings | | | | | | | 10

|Co. | | | | | | |

| | | | | | | |

75-mm. field gun, |Bethlehem Steel | 1| 7| 30| 38| 47| 33| 62

model 1917 |Co. | | | | | | |

| | | | | | | |

3-inch anti- | do. | | | 6| 7| 5| 4| 12

| | | | | | | |

| | | | | | | |

4.7-inch gun |Bethlehem Steel | | | 9| 10| 8| 28|

|Co. | | | | | | |

| | | | | | | |

| | | | | | | |

155-mm. howitzer |Bethlehem Steel | | 10| 26| 51| 9| 37| 25

|Co. | | | | | | |

| | | | | | | |

|Standard Forgings | 2| 3| | 10| 20| 55| 44

|Co. | | | | | | |

| | | | | | | |

|Standard Steel Co.| | | | | 15| 54| 64

| | | | | | | |

155-mm. gun |Bethlehem Steel | | | | | 1| 9|

|Co. | | | | | | |

| | | | | | | |

|Pa. | | | | | | |

| | | | | | | |

|Standard Steel | | | | | | 6| 4

|Pa. | | | | | | |

| | | | | | | |

| | | | | | | |

| | | | | | | |

8-inch howitzer |Midvale Steel Co. | 1| 5| 11| 10| 19| 5| 67

| | | | | | | |

|Co. | | | | | | |

| | | | | | | |

|Co. | | | | | | |

| | | | | | | |

|Co. | | | | | | |

| | | | | | | |

------------------+------------------+-----+----+-----+----+----+----+-----

Total | | 6| 26| 114| 174| 175| 440| 525

------------------+------------------+-----+----+-----+----+----+----+-----

------------------+--------------------------------------------------+-----

Caliber. | Contractor. | 1918 |Total.

| +-----+----+-----+----+----+----+-----

| |July.|Aug.|Sept.|Oct.|Nov.|Dec.|

------------------+------------------+-----+----+-----+----+----+----+-----

75-mm. field gun, |Bethlehem Steel | 23| 7| 1| 180| 1| | 352

|Pa. | | | | | | |

| | | | | | | |

|Standard Forgings | 29| 2| | | | | 149

| | | | | | | |

|Buckeye Steel | 10| | | | | | 164

| | | | | | | |

75-mm. field gun, | do. | 419| 325| 322| 658| 181| 224|2335

| | | | | | | |

|Standard Forgings | 32| 275| 310| 471| 245| 39|1382

|Co. | | | | | | |

| | | | | | | |

75-mm. field gun, |Bethlehem Steel | 61| 69| 121| 76| 247| 47| 839

model 1917 |Co. | | | | | | |

| | | | | | | |

3-inch anti- | do. | 10| 6| 46| 112| 109| 5| 322

| | | | | | | |

|Heppenstall Forge | | | 3| 51| 15| 13| 82

| | | | | | | |

4.7-inch gun |Bethlehem Steel | 70| 94| 66| 14| | 43| 342

|Co. | | | | | | |

| | | | | | | |

|Heppenstall Forge | | 6| 18| 21| 25| 10| 80

| | | | | | | |

155-mm. howitzer |Bethlehem Steel | 5| | 11| 52| 19| 32| 277

|Co. | | | | | | |

| | | | | | | |

|Standard Forgings | 89| 74| 169| 127| 157| 10| 760

|Co. | | | | | | |

| | | | | | | |

|Standard Steel Co.| 82| 130| 93| 100| 100| 20| 658

| | | | | | | |

155-mm. gun |Bethlehem Steel | 21| 7| 5| 4| 1| | 48

|Co. | | | | | | |

| | | | | | | |

|Edgewater Steel | | 4| 13| 21| 24| 5| 67

|Pa. | | | | | | |

| | | | | | | |

|Standard Steel | 21| 14| 23| 41| 21| 9| 139

|Pa. | | | | | | |

| | | | | | | |

|Tacony | | 3| 15| 31| 26| | 75

| | | | | | | |

|American Bridge | | | | 8| 7| 10| 25

| | | | | | | |

8-inch howitzer |Midvale Steel Co. | 29| 2| | | | | 149

| | | | | | | |

240-mm. howitzer |Bethlehem Steel | | 30| 16| 16| 19| 16| 97

|Co. | | | | | | |

| | | | | | | |

|Edgewater Steel | | | 1| | | 14| 15

|Co. | | | | | | |

| | | | | | | |

|Tacony Ordnance | | | 4| 15| 3| 12| 34

|Co. | | | | | | |

| | | | | | | |

|Watertown Arsenal | | | |[10]| | 7| 7

------------------+------------------+-----+----+-----+----+----+----+-----

Total | | 872|1074| 1259|2031|1214| 530|8440

------------------+------------------+-----+----+-----+----+----+----+-----

[10] Figures in first table indicate delivery of completed sets of

forgings only. Deliveries of finished and accepted gun forgings, not in

complete sets, were made in carload lots and in other large quantities

by various factories prior to the dates when their receipt of machine

tools enabled them to produce completed sets. For instance, Watertown

Arsenal made its first carload shipment of forgings on Oct. 28, 1918.

CANNON MACHINING AND ASSEMBLING.

_Progress of the work of machining and assembling cannon at the

various factories during the war._

+------------+--------------+-----+-----------------------------------

| |1917 | 1918

| +-----+-----+-----+-----+-----+-----+-----

Caliber. | Contractor. |Dec. |Jan. |Feb. |Mar. |Apr. |May. |June.

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

75-mm. |Symington- | | | | | | |

1916 |N. Y. | | | | | 1 | 51 | 81

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Gun Co., | | | | | | |

|Wis. | | | | | | 8 | 18

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Arsenal, | | | | | | |

|N. Y. | 4 | 38 | 18 | 14 | 26 | 35 | 8

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Steel Co. | | | | | | |

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

75-mm. |Symington- | | | | | | |

1897 |Co. | | | | | | |

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Gun Co. | | | | | | |

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

75-mm. |Bethlehem | | | | | | |

1917 | | 1 | 7 | 30 | 38 | 47 | 33 | 62

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

gun |Co., Detroit, | | | | | | |

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

gun, | | | | | | | |

15-pdr. | | 3 | 16 | 24 | 16 | 2 | | 11

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

1906 |Madison, Wis. | | | | | | |

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Arsenal | | | | | | | 6

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

155-mm |American | | | | | | |

|Co., | | | | | | |

|Erie, Pa. | | | 3 | 10 | 16 | 28 | 75

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

155-mm. |Bullard | | | | | | |

gun |Engine | | | | | | |

|Co., | | | | | | |

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Arsenal | | | | | | |

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

howitzer |Steel Co. | | | | 34 | 38 | 8 |

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

240-mm. |Watervliet | | | | | | |

|Arsenal | | | 34 | 38 | 8 | |

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

Total | | 8 | 61 | 75 | 112 | 130 | 163 | 261

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

+------------+--------------+-----------------------------------------

| | 1918

| +-----+-----+-----+-----+-----+-----+-----

Caliber. | Contractor. |July.| Aug.|Sept.| Oct.| Nov.| Dec.|Total.

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

75-mm. |Symington- | | | | | | |

1916 |N. Y. | 61 | 88 | 48 | 74 | 12 | | 416

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Gun Co., | | | | | | |

|Wis. | 20 | 38 | 27 | 5 | | | 116

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Arsenal, | | | | | | |

|N. Y. | | 8 | | 5 | 5 | 5 | 166

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Steel Co. | | 1 | 1 | | | | 2

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

75-mm. |Symington- | | | | | | |

1897 |Co. | | | | | | |

model | | | | 1 | 52 | 50 | 136 | 239

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Gun Co. | | | 1 | 2 | 6 | 26 | 35

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

75-mm. |Bethlehem | | | | | | |

1917 | | 61 | 69 | 121 | 76 | 247 | 47 | 839

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

gun |Co., Detroit, | | | | | | |

|Mich. | 1 | 7 | 19 | 48 | 29 | 30 | 134

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

gun, | | | | | | | |

15-pdr. | | 9 | 4 | 3 | 2 | 5 | 1 | 96

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

1906 |Madison, Wis. | | 5 | 7 | 31 | 23 | 32 | 98

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Arsenal | 8 | 10 | 22 | 40 | 27 | 7 | 120

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

155-mm |American | | | | | | |

|Co., | | | | | | |

|Erie, Pa. | 110 | 248 | 206 | 350 | 231 | 179 |1,456

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

155-mm. |Bullard | | | | | | |

gun |Engine | | | | | | |

|Co., | | | | | | |

|Conn. | 1 | | 14 | 28 | 18 | 36 | 97

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

" |Arsenal | 1 | | | 23 | 4 | 4 | 32

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

howitzer |Steel Co. | | 28 | 22 | 33 | 14 | 14 | 191

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

240-mm. |Watervliet | | | | | | |

|Arsenal | | 1 | | | 1 | | 2

+------------+--------------+-----+-----+-----+-----+-----+-----+-----

Total | | 272 | 507 | 492 | 769 | 672 | 517 |4,039

+------------+--------------+-----+-----+-----+-----+-----+-----+-----