798 Transactions of the American Institute. 



between that imported and Mr. Mowbray's make, is, that a twelve 

 inch column of fluid nitro-glycerine, imported, will expand in freezing 

 three-fourths of an inch in height, while that of Mr. Mowbray's 

 shrinks half an inch. This is supposed to occur from the presence of 

 nitrous gas in the one and an absence of it in the other. 



Mr. Mowbray and the electrician, Mr. Brown, informed me that 

 they had uiade experiments with frozen nitro-glycerine ; among which 

 a tin tube was nearly filled with the liquid, then frozen. Gun-cotton 

 in one case was placed over it ; in another, fulminate ; in another, 

 gun powder. To these were attached electric fuses, the tubes placed 

 between heavy blocks of ice, and fired. The result was to drive the 

 frozen nitro-glycerine out of the tube into the ice, in the form of a 

 candle ; no explosion of the nitro-glycerine taking place. 



Mr. Mowbray, from this and other experiments, concludes that this 

 agent may be transported quite safely in the frozen state. 



There are two routes from New York to the Hoosic Tunnel. One, 

 by the New IIa*ren railroad to Bridgeport, thence by the Housatonic 

 railroad to Pittsfield, Mass., then the Pittsfield and North Adams 

 railroad; the other and quicker is the Hudson river railroad to Troy, 

 thence by the Troy and North Adams railroad. 



Dr. J. F. Boynton remarked that he had seen nitro-glycerine 

 exploded on an anvil in Washington, by being struck with a smooth- 

 faced hammer, and only that part which came in contact with the 

 face of the hammer exploded. 



Dr. D. D. Parmelee stated that nitro-glycerine will burn like oil, 

 and not explode. But the least dirt, such as straw, or any other 

 foreign substance causes immediate decomposition. In the room 

 where the nitro-glycerine is made, potash is used to neutralize its 

 explosive qualities, and such places where it may have dropped on 

 the floor are covered with the potash. 



The chairman presented the following interesting scientific items : 



Coating for Cast Ikon. 

 To protect cast iron work from oxydation or rust, W. Leike of 

 Hanover has sucwissfully used a mixture consisting of two parts of 

 water-glass (silicate of soda) in solution, of the strength indicated by 

 twenty degrees Baume, and one part of zinc oxyd. The material, 

 laid on as a thick varnish, gives the iron an enameled appearance, 

 and is not injured by the application of soap and water or other alka- 

 line liquids. 



