24 MODERN SCIENCE READER 



use of a small charge of dry guncotton with a fulminate 

 detonator, and since it can be stored and used in the moist 

 state, it becomes one of the safest explosives for use in 

 submarine mines, torpedoes, etc. 



Nitroglycerin is a substance of a similar chemical nature 

 to nitrocellulose, the principles of its formation and puri- 

 fication being very similar, only in this case the materials 

 and product are liquids, this rendering the operations of 

 manufacture and washing much less difficult. The glycerin 

 is sprayed into the acid mixture by compressed air in- 

 jectors, care being taken that the temperature during* 

 nitration does not rise above 30 C. The nitroglycerin 

 formed readily separates from the mixed acids, and being 

 insoluble in cold water, the washing is comparatively simple. 



This explosive was discovered by Sobrero in 1847. 

 Nitroglycerin is an oily liquid readily soluble in most 

 organic solvents, but becomes solid at three or four degrees 

 above the freezing point of water, and in this condition is 

 less sensitive. It detonates when heated to 257 C., or by 

 a sudden blow, yielding carbon dioxide, oxygen, nitrogen, 

 and water. Being a fluid under ordinary conditions, its 

 uses as an explosive were limited, and Nobel conceived the 

 idea of mixing it with other substances which would act 

 as absorbents, first using charcoal and afterward an in- 

 fusorial earth, ' ' kieselguhr, " and obtaining what he termed 

 ' ' dynamite. ' ' 



In 1875, Mr. Alfred Nobel found that "collodion cotton" 

 soluble guncotton could be converted by treatment with 

 nitroglycerin into a jelly-like mass which was more trust- 

 worthy in action than the components alone, and from its 

 nature the substance was christened "blasting gelatin." 

 The discovery is of importance, for it was undoubtedly the 

 stepping-stone from which the well-known explosives bal- 

 listite, filite, and cordite were reached. In 1888, Nobel 

 took out a patent for a smokeless powder for use in guns, 

 in which these ingredients were adopted with or without 

 the use of retarding agents. The powders of this class 



