vs.
Geo. M. Mowbray, J. H. King, Chas. Lobb, W. L. Holbrook, James Dickey and A. D. Hatfield.
As the sworn affidavits in the above case, now pending, are of great importance in substantiating, both practically and legally, the claims urged in previous observations, on behalf of the “Mowbray system” of manufacturing and using Nitro-Glycerin, I give below the substance of the testimony.
Evidence of George F. Barker, Professor of Physiological Chemistry and Toxicology in the Medical Department of Yale College.
“I have carefully examined the several re-issued patents, Nos. 3,377, 3,378, 3,379, 3,380, 3,381 and 3,382, the four former being divisions A, B, C and D, of the re-issued patent, granted upon the surrender of the original patent No. 50,617, dated October 24th, 1865, and the two latter divisions 1 and 2 of the original patent, also granted to the assignees of Alfred Nobel, on surrender of the original patent No. 57,175, dated August 14th, 1866, granted to said Alfred Nobel. I would further state that in the specifications of the before-mentioned re-issues it is asserted that Sobrero discovered that Glycerin was capable of giving, when, mixed with sulphuric and nitric acids, a substance analogous to gun cotton, which is true; and that the specifications of the said patents further state that “Sobrero abandoned further research with the declared opinion that its combustion or explosion could not be managed”; which statement, having read all which Sobrero is believed to have published upon the subject, viz.: his papers published in the Comptes Rendus de L’Academie des Sciences, Volume XXIV., page 247, printed in Paris A. D. 1847, and in the Repertoire de Chimie Applique, Volume II., page 400, printed in Paris in 1860, I have entirely failed to find recorded by him as his opinion.”
J. E. de Vrij also, in a communication to the British Association, which was read in July, 1851, and is published in the report of the association for the year 1851, page 52 (Notices and Abstracts), states in regard to Nitro-Glycerin, that it “explodes at a moderate heat, as was shown by experiment, detonating when the drops of Nitro-Glycerin on paper were struck a smart blow with a hammer.”
The before-mentioned re-issued patents further assert that “in order to explode the whole, or even a large proportion of the mass of Nitro-Glycerin, it is necessary to subject it to confinement or restraint”; which assertion is untrue, for Nitro-Glycerin, when freely exposed to the air in an open vessel or plate, may be and is capable of being readily exploded, without confinement, restraint, or pressure, as I have proved by experiment made at North Adams, on the 17th day of May, 1870, in exploding upon two occasions a quantity of Nitro-Glycerin in an open saucer with great violence, on which occasion the Nitro-Glycerin was exploded by simple concussion in open vessels, the fulminate cap used as the exploder being suspended above the surface of the Nitro-Glycerin in the saucer, and distant nearly two inches from it; so that the application of heat and pressure, or of either of these agencies, is unnecessary.
The said re-issued patents further assert, that “the degree of confinement must be sufficient to allow a pressure upon the Nitro-Glycerin to an extent that 360°F will be realized, so that decomposition will take place before the liquid can escape the force or heat of the evolved gases of a percussion cap, etc.”; whereas I found on the above occasion that when water was interposed between the Nitro-Glycerin and the percussion cap, so that no measurable increase of temperature (much less 360°F) could possibly occur in the former, the Nitro-Glycerin could be exploded.
In the first experiment three tubes, closed at bottom and containing half an ounce of Nitro-Glycerin each, were placed in water in a tumbler, being supported an inch from the bottom. Into the water in the tumblers, and outside of the tubes, distant from them nearly an inch, the fulminate cap was put. This was then fired, and caused the explosion of the Nitro-Glycerin through the intervening water. In the second experiment, using a tub of water in which eleven tubes containing Nitro-Glycerin were placed, the explosion of six fulminate caps failed to fire the Nitro-Glycerin, the distance from the tubes at which they were placed, nearly or quite ten inches, being too great. In the third experiment five such tubes of Nitro-Glycerin were suspended in a tub of water distant four or five inches from each other; the fulminate cap being inserted in the middle tube. On firing this cap the Nitro-Glycerin in all the tubes was exploded, as judged from the violent effects produced.
The said re-issued patents further assert that “Gun-cotton will explode in proportion to the degree of confinement, igniting at 266°F.” The celebrated chemist of the English War Department, F. A. Abel, who has made the most extended researches upon gun cotton on record, asserts in his paper published in the Philosophical transactions for 1869 (an abstract of which appears in the Journal of the Chemical Society of London for 1869, Volume XXIII., page 11,) “that rows of detached masses of gun cotton, placed on the ground, and extended 4 or 5 feet, have been exploded with most destructive results by firing a small detonating tube in contact with the piece of compressed gun cotton which formed one extremity of the row or train, the explosion of the entire quantity being apparently instantaneous and equally violent throughout.” And further that these and similar experiments “appear to indicate decisively that such explosion is not a result of the heat developed by the explosion of the detonating materials.”