It was stated that this sample requires a detonating primer to cause proper action, and that it is believed to be stronger than sample D.

Sample D was also prepared at Fort Hamilton by adding 24 per cent of specially prepared pyroxiline, with a trace of aniline dye, to sample A. An air pump had been procured and was used to assist the dissolution. The result was a semifluid jelly which flowed quite sluggishly from the jar, but was loaded in this manner.

In all forms this explosive must be kept carefully corked, as exposure to the air induces evaporation of the more volatile ingredients, leaving a dry residue which exhibits much more sensitiveness. This fact was stated by Prof. Mendeleff, and was verified for sample C by the committee. He also stated that an alcoholic solution of caustic potash should be used for cleaning the jars, etc., as it causes a safe chemical reaction, the results being glycerine and potassium nitrate.

Several days were required for the preparation of a few pounds of the last three samples from sample A; but as the facilities at the fort were not well adapted for such work, and especially as an air pump was wanting until nearly the end of the trials, no estimate of the time required for making these explosives can be based on this experience. None of the samples presented by the company were as free from the objection of fluidity as the board had anticipated from the correspondence; and sample A was absolutely rejected on account of this defect which certainly would exclude it from the military service. Samples B and C were objectionable on the same ground, but to a less degree; sample D was prepared at the request of the committee to overcome this defect as far as possible. The inventor explained that in the solid form the sensitiveness of his explosive would increase to a dangerous degree, and that a semifluid jelly marked the safe limit in this respect. The volatile nature of some of the ingredients is another serious objection for the military service.

The relative strength of samples B, C, and D, compared with other explosives, was tested in the usual manner in the five trials numbered 51 to 55 in the table. They indicate that perunite takes rank as decidedly the most powerful explosive thus far tested, the ratios; compared with explosive gelatine, being: For sample B, 12.22

C,

10.28

= 1.12.

17.59

1.44; for sample

15.47 1.28; and for sample D, 9.19 How much of this 12.14 extraordinary power is due to the physical condition of the explosive and how much to the chemical reactions can not be inferred from these trials.

This new explosive is evidently of great interest from a scientific point of view, but so long as it can be produced only in a form possessing more or less fluidity it is unsuited for the military service, and no further trial of it is recommended.

RECAPITULATIONS AND RECOMMENDATIONS.

Summing up the above, your committee recommends: (1) That experiments with Emmensite in shells fired from powder guns be conducted in the 11-inch gun at as early a day as practicable; (2) that similar trials with shells charged with wet gun cotton packed with paraffine and Carnauba wax be prosecuted without loss of time; (3) that trials in the 7-inch gun be made with explosive gelatine in shells diaphragmed on the principles embodied in pattern (c) already tested in earth; (4) that early experiments on the rotating machine be made

with rackarock having the ingredients mixed; and that if the results are favorable the trials be continued in shells fired from powder guns. Sufficient progress has been made in these subterra trials to warrant a classification of the explosives, already tested, according to their relative merit in shells designed to form craters in earthen parapetsupon the assumption (by no means established) that modes can be devised for firing them safely without reducing their natural density of loading. This relative merit is shown by the product of their relative earth-lifting power, as above determined, by their weights when charged in the standard shell cavity (192 cubic inches). These figures of course are chiefly of practical value as indicating in what direction experiments should be pushed. They are the following:

The following programme is suggested for the continuation of the trials in the early future:

With subterra shells.-Such tests as may be needed from time to time to determine the merits of any new explosive or new modes of charging which may be approved for trial by the board.

With the rotating machine.-A sufficient number of trials to determine whether the danger of premature explosion is to be apprehended from the rotation caused by the rifling when shells thus charged are fired from powder guns: (1) With explosive gelatine in shells having longitudinal and transverse diaphragms combined; (2) in shells without diaphragms containing wet gun cotton packed with paraffine and Carnauba wax; (3) in similar shells containing Emmensite; (4) in similar shells containing rackarock mixed; and (5) in similar shells containing explosive gelatine packed according to the Stevens method.

With the 7-inch muzzle-loading rifle.-(a) Ten shells, with diaphragms as above, loaded with explosive gelatine containing 4 per cent of camphor. Firing to be over water, with propelling charges of about 25 pounds of Dupont's hexagonal E. V. K. powder, or its equivalent, with an elevation of about 110, and without a fuse. (b) Five shells, without diaphragms, charged with wet gun cotton packed with paraffine and Carnauba wax, under similar conditions. (c) If previously successful on the rotating machine, five charges of rackarock with ingredients mixed.

With the 11-inch muzzle-loading rifle.-Ten shells to be fired loaded with Emmensite, ten more loaded with wet gun cotton, and ten with explosive gelatine, when these explosives have passed a successful test in the 7-inch rifle. The charge in all cases to be regulated to give as severe a shock and as high an initial velocity as the gun will bear; no fuses to be used; the range to be over water, and the firing to be done at rather high angles of elevation.

Fuses with shells charged with high explosives.-It is regarded by the committee as extremely important to prosecute the trials recommended in the first report so soon as samples can be procured.

Remarks. In order to carry out this programme special shell must be provided for use in the rotating machine. It is thought that when diaphragms are to be used the shell should have octagonal cavities, and that the others should be cylindrical in form. In all of them the rough H. Ex. 12-6

ness of the interior surface should correspond to that of the ordinary service shell. In order to determine the advantageous thickness of diaphragm, several different thicknesses should be tried with charges of dry sand. Two shells for diaphragms and three without them will probably be sufficient.

As Emmensite has already been tried in the 7-inch and smaller guns, its test in the 11-inch gun can be proceeded with at once. The other trials in the 11-inch gun should follow corresponding trials in the 7-inch gun and on the rotating machine.

In the conduct of these experiments discretion must be used in making a greater or less number of trials, without too rigid an adherence to the programme as laid down. Respectfully submitted.

HENRY L. ABBOT,
Colonel of Engineers,

Brevet Brigadier General, U. S. Army.
A. MORDECAI,

Colonel, Ordnance Department, U. S. Army.

Maj. Gen. JOHN M. SCHOFIELD,
President Board of Ordnance and Fortification.

Appendix F.

SITES FOR PROVING GROUNDS.

[House Ex. Doc. No. 148, Fifty-first Congress, first session.]

TESTING AND PROVING HEAVY ORDNANCE.

2

LETTER FROM THE SECRETARY OF WAR, TRANSMITTING A REPORT OF THE BOARD OF ORDNANCE AND FORTIFICATION RELATIVE TO A SITE FOR TESTING AND PROVING HEAVY ORDNANCE.

WAR DEPARTMENT, Washington City, January 22, 1890.

The SPEAKER OF THE HOUSE OF REPRESENTATIVES:

The Secretary of War has the honor to transmit to Congress the report of the Board of Ordnance and Fortification, dated January 18, 1890, and accompanying papers, made in compliance with so much of the act making appropriations for the support of the Army for the fiscal year ending June 30, 1890 (25 Stat., 833) as requires an examination and report "upon a site or sites for ordnance testing and proving ground to be used in the testing and proving of heavy ordnance, having in view in the selection of said site or sites their accessibility by land and water, means of transportation, and suitability for the purpose intended, and also the actual and reasonable cost, and the value of the land embraced in said site or sites, and the least sum for which the same can be procured."

REDFIELD PROCTOR,
Secretary of War.

BOARD OF ORDNANCE AND FORTIFICATION,

WAR DEPARTMENT, Washington, D. C., January 18, 1890.

SIR: As directed by the act of Congress making appropriations for the support of the Army for the fiscal year ending June 30, 1890, and for other purposes, the Board of Ordnance and Fortification has made an examination of "a site or sites for ordnance testing and proving ground to be used in the testing and proving of heavy ordnance, having in view in the selection of said site or sites their accessibility by land and water, means of transportation, and suitability for the purpose

83

intended, and also the actual and reasonable cost, and the value of the land embraced in said site or sites, and the least sum for which the same can be procured;" and has now the honor to submit the following report thereon.

The work to be done at an ordnance testing and proving ground is of two distinct classes, which if necessary may be performed at two different sites. Thus every gun, before issue for service, must be fired a few times to verify the perfection of the breech mechanism and the proper adjustment of the several parts of which it is composed. This is simply to prove the guns when fired with service charges, and can be done at any site that fulfills the following conditions:

(a) It should be in the near vicinity of the gun factory, with ready means of intercommunication. This would reduce the loss of time and cost of transfers to a minimum, and would enable slight corrections to be made in the same shops and by the same workmen who have fabricated the guns.

(b) The area must be large enough, when provided with suitable butts, to guard against accidents which may be caused in the neighborhood by projectiles escaping from control.

(c) Sufficient space should intervene between the firing point and private establishments, to prevent the noise from being an annoyance to the population. As the distance between the guns and the butts will always be limited to a few hundred yards, an extensive tract is not necessary for this purpose; an area of about 4 square miles, in approximately a circular shape, will, if situated in a sparsely-populated district, fulfill the requirements.

The other class of work for which an ordnance proving ground is necessary is of entirely a different character. It comprises a thorough and exhaustive test of new types of guns, new carriages on which to mount them, new explosives, new fuzes and iguiting mechanism, armor plates of new types and samples delivered for test by manufacturers, new devices for protecting guns against hostile fire, in a word, the researches demanded by modern progress in developing the countless varieties of new war material.

Doubtless, if it were practicable to combine these two classes of work at a single site, the best solution of the problem of where to select an ordnance proving ground would be reached, but a personal examination of the vicinity of the new gun factory at Watervliet Arsenal has convinced the Board that this can not be done. Two sites are demanded for efficient service.

The following conditions should be fulfilled by a site suited to the general investigations indicated above.

(1) As to dimensions.-Unless the tract be separated by water from land in the vicinity, considerable width is needful to avoid danger to surrounding property. Projectiles are liable to erratic flights, especially after the first graze, and the fragments caused by bursting charges of high explosives in shells scatter over a wide area. Two miles is by no means an excessive estimate for the width required. As to length, certain facts are to be considered. By far the greater part of the firing will be at comparatively short ranges; for such ranges are best adapted to the determination of initial velocity and accuracy of flight and to testing armor plates and new types of fortification. It is true that projectiles now have a flight of 10 miles and upward, but these extreme ranges can be computed by modern improved methods with sufficient accuracy to meet most practical demands. To throw light upon this important matter of the length needful for a moderu proving