the violent headache produced by 1/250 of a grain of Nitro-Glycerin or Glonoin, as he proposed to call it, and killed a cat with three drops. Field, in 1858, Pharmaceutical Journal, Volume XVII., page 544, confirmed these results; but Harley and Fuller, reported in the same place, were unable to obtain them by using other specimens of Nitro-Glycerin, though they largely increased the dose. Field consequently says, place given, page 627, “I am daily more convinced of two important facts connected with it, viz.: the great variation in the strength of different specimens, and the very marked difference in the susceptibility to its influence.” In further support of the opinion that several allied but distinct Nitro-Glycerins have been made, the wide difference in density and in congealing point may also be mentioned. In my opinion the best effect cannot be obtained with commercial acids, owing to their insufficient strength. I have witnessed at the defendant Mowbray’s works, at the West shaft of the Hoosac Tunnel, the preparation of the acids used for making the Nitro-Glycerin, commercial acids being found deficient in strength, and in my opinion it is to the use of these stronger acids, combined with the method described in defendant’s patent, as above mentioned, that the stability, efficiency, and, above all, the freedom from noxious gases and vapors of the products of combustion of defendant’s Nitro-Glycerin is due, when contrasted with that made by complainant, which I have been informed and verily believe is made with acids of commercial strength, and produces, when exploded in a mine, gases and vapors highly deleterious to health. I have further examined the patent No. 93,113, dated July 27th, 1869, granted to Mowbray, for exploding Nitro-Glycerin, and have experimented with the same, the explosions hereinbefore enumerated having been effected by the method therein described. And this deponent finds that by said Mowbray’s process of exploding Nitro-Glycerin, as claimed in his patent, confinement, restraint, or pressure is wholly unnecessary. In my opinion the same is true in exploding Nitro-Glycerin on a large scale, as I have been informed, and verily believe that upwards of one thousand explosions of Nitro-Glycerin are made weekly in the Hoosac Tunnel by the mode so described in said patent. [Illustration]