Nitro- Glycerine, 



101 



we knew that the lesson learnt by Granger in his sleigh- 

 ride was confirmed, and our teamsters, magazine guards, 

 and customers, could rest assured that if they would keep 

 their nitro-glycerine in store, well iced, explosion would be 

 impossible. 



Paraphrasing the language of Professor Tyndall, in his 

 preface to Hours of Exercise in the Alps : " For rashness, 

 ignorance, or carelessness, nitro-glycerine leaves no margin ; 

 and to rashness, ignorance, or carelessness, three-fourths of 

 the catastrophes which shock us, are to be traced." 



Properties. — Chemically pure tri-nitro-glycerine be- 

 comes solid at 45° F. Nobel states 55° F., but that is an 

 error. Shaffher, in a patent for nitro-glycerine-charged 

 shells, provides for the nitro-glycerine expanding in congeal- 

 ing ; if so, it possesses difTeren t properties from what we make , 

 for tri-nitro-glycerine shrinks about one-twelfth its bulk in 

 passing from the fluid state at 70° to the congealed state 

 it assumes when exposed to ice and salt. The solid state, 

 moreover, we regard as the safest, for the reasons given, 

 and the printed statements in German works, Count Rud- 

 berg's assertion, for instance, to the contrary, are erroneous. 

 The temperature at which the acids and glycerine combine 

 (as may be inferred from the action of these acids on an 

 organic matter, glycerine), varies the product, so that if a 

 certain temperature be exceeded, complex products are pro- 

 duced, which change the resulting product of nitro-glycerine 

 very seriously, and, what is desirable to notice, influence and 

 tend to subsequent spontaneous decomposition. 



As regards the efforts of inventors to render nitro-gly- 

 cerine safe by mixing it with inert matters, I think they 

 have not looked to the purity of the nitro-glycerine they 

 have attempted to make, and finding what they have made 

 liable and ready to decompose, instead of tracing it to its 

 true cause, careless preparation, have tinkered to cure a 

 disease that greater care would have prevented, and so 



