Nitro Glycerine, as used in the Construction of the Hoosac 

 Tunnel. By Professor George M. Mowbray, of 

 North Adams, Mass. 



[Read before the Albany Institute, Oct. 17, 1871.] 



At the sixteenth anniversary of the British Association 

 for the Advancement of Science, held at Southampton, 

 England, in the summer of 1846, much interest was ex- 

 cited by the exhibition and description, of Professor Schon- 

 bein's gun cotton, which was then proposed as a substitute 

 for gunpowder. ISTo information, however, was given at 

 that meeting, as to its real nature, or mode of preparation, 

 which were then kept perfectly secret ; nor were the mem- 

 bers allowed to examine it closely, lest they should get 

 some clue to the secret. Sir John Herschel remarked 

 of it : " It might in the next generation arm mankind 

 with the*very wildest powers, by which they could tear up 

 rocks, and almost call down lightning." 



In the month of April, 1847, being six months after a 

 patent was granted, in conformity with the practice in 

 patent cases in England, the specification of the process 

 appeared : describing the invention as consisting in the 

 manufacture of explosive compounds applicable to mining 

 purposes and to projectiles, and as substitutes for gun- 

 powder, by treating and combining matters of vegetable 

 origin with nitric and sulphuric acids, preferring cotton. 

 This cotton is to be immersed in a mixture of one part 

 nitric acid, specific gravity 1.450 to 1.500, with three parts 

 sulphuric acid, specific gravity 1.850, allowed to cool after 

 mixing to 50° or 60° F. After removing the cotton, press- 



