272 ANNUAL, EEPORT SMITHSONIAN INSTITUTION, 1908. 



is nitrated solvent naphtha. It must be embarrassing to the inventors 

 to see such improbable accounts of manufacturing costs and exagger- 

 ated effects produced by the explosive published in newspapers. 



II. 



I have mentioned in my previous lecture that Sobrero invented 

 nitroglycerin in 1847. It is known that, although he recognized the 

 value of this invention for civil and military blasting purposes, prac- 

 tically^ no use was made of it until 1867, when Alfred Nobel invented 

 djaiamite, and was not deterred by accidents and prejudice from 

 introducing it into the service of mankind. You know that before 

 this time Mowbray, in Massachusetts, manufactured nitroglycerin 

 and carried it into the mines in the frozen state. 



Nobel devised processes for the manufacture of nitroglycerin on a 

 large scale, and the machinery for it was constructed to his ideas by 

 his lifelong adjutant, Mr. Alarik Liedbeck, of .Stockholm. Since 

 there is a full description of all the apparatus in use in my book on 

 The Manufacture of Explosives, which appeared in 1895, I can con- 

 fine myself to dealing with progress made since that date. You will 

 find described in this book two kinds of apparatus for nitrating 

 glycerin, such that have a helical revolving stirrer for mixing pur- 

 poses and such that are agitated by compressed air. Occasionally 

 both mechanical and compressed air stirring are used. One has learned 

 in time to control the operation of nitration more efficiently, and this 

 inspired confidence to increase the size of the apparatus, I believe 

 the largest apparatus made in lead nitrates 680 kilograms of glycerin 

 at one operation, while in America and South Africa steel apparatus 

 with mechanical stirring gear are mostly used, some nitrating 1,000 

 kilograms at a time. In one United States works they have gone so 

 far as to have four such steel nitrators, each for a charge of 1,000 

 pounds of glycerin, in one room and driven from one main shaft, but 

 present practice is to have two such nitrators in one building. In this 

 country one would not allow more than one nitrating apparatus to be 

 used at a time. Of course each nitrator is provided with a series of 

 lead or steel coils through which cold water circulates, and it has now 

 become frequent to install a refrigerating plant and to circulate water 

 of only 10° C. and less through the coils. 



With regard to the composition of the nitrating mixture, it has 

 been customary in well-conducted factories during the last twenty 

 years or so to nitrate 110 kilograms of glycerin in a mixture of 300 

 kilograms of nitric acid of about 93 to 94 per cent monohydrate and 

 500 kilograms of sulphuric acid of 96 per cent monohydrate (and not, 

 as Sir Frederic Nathan and Mr. Kintoul stated, 100 parts of glycerin 



