“I am employed in exploding the Nitro-Glycerin in the holes drilled by the miners in the Oil Creek Tunnel, Pa. I used Nitro-Glycerin from the Lake Shore Nitro-Glycerin Works, which is very different to that of the United States Blasting Oil Company, of New York, and requires a different mode of explosion. I do not use any of the methods described in Nobel’s patent of October 24, and re-issued April 13, 1869, for exploding, for the methods therein described would only explode it, if at all, which I doubt, by hazard, and not with certainty, owing to the peculiar properties of the Lake Shore Nitro-Glycerin as compared with what I have seen and used as the Shaffner, or Nobel’s Nitro-Glycerin. I endorse all the previous evidence as to the difference between the Nobel or Shaffner Nitro-Glycerin, and that made under Mowbray’s patent. The method I have used to explode this Nitro-Glycerin, at the Oil City Tunnel, consists in what is known as the Austrian battery and electric fuse and fulminating shell; that is, an electric machine, whose exciting plate is made of ebonite or hard rubber, with insulated and conducting wire terminals, which are from ¹/₁₆ to ¹/₃₂ of an inch apart, and between those terminal points a priming composition is inserted, through which the electric spark being passed, such priming ignites, giving a flame (insufficient to explode the Nitro-Glycerin, but) sufficient to inflame a fulminating compound, of which there is a heavy charge, and this fulminating compound being exploded by the priming composition, explodes the Nitro-Glycerin. I have never used the method of exploding with gunpowder as described in the Nobel patent, No. 50,617, in the tunnel aforesaid, nor elsewhere, but I have witnessed attempts to explode the Nitro-Glycerin used under Mowbray’s Patent by means of fuse and gunpowder, as described by Nobel, where that method failed.” February 19, 1870. GEORGE WEST. [Illustration: Sinking the Central Shaft.] Evidence of H. Julius Smith.