"^■64 NITRO-GLYCERINE. 



There have been a great number of substances proposed as a sub- 

 stitute for the kieselguhr, but none seem to answer all purposes 

 quite so well. Dualin consists of sawdust or lignine soaked with 

 nitro-glycerine. It is the invention of Lieut. Ditmar, who brought 

 over 100 lbs. of it to the United States in a carpet bag. It is said 

 by the way, that the first nitro-glycerine brought to America was 

 carried by a passenger in one of the large ocean steamers, who kept 

 it under his pillow. Some of it was used successfully in the Hoosac 

 Tunnel. 



The industrial manufacture of nitro-glycerine is attended with 

 considerable danger, and requires great precautions. The operations 

 are carried on under open circular sheds, covered with roofs of bitu- 

 minized paper. The floors slope from the centre towards the circum- 

 ference, and a constant flow of water is kept up to carry away any 

 nitro-glycerine that might otherwise accumulate on them. The 

 mixed acids are placed in cylinders of glass, stoneware or cast iron,, 

 immersed in water cooled to 10° C The nitro-glycerine is introduced 

 by means of a tap, drop by drop, and a constant rotary motion is 

 kept up by means of a current of air. A large tiibe is connected 

 with the cylinders to carry off vapours and prevent the headaches to 

 which the workmen would otherwise be subject. The proportions 

 recommended by Girard, Millot and Vogt * are one part, by weight 

 of glycerine, at 30° Baume, two parts of nitric acid at 48°, and four 

 parts of sulphuric acid at 66°. When all the nitro-glycerine has 

 been added, the mixture is poured into six times its weight of 

 water, and the nitro-glycerine which falls to the bottom is washed 

 twice with water, then with an alkaline solution, and then with 

 water. 



In the manufacture of dynamite the dry kieselguhr is put into 

 stoneware vessels, and moistened with nitro-glycerine in the proper 

 tion of '25 % of the earth to 75 % of the nitro-glycerine. 



The analysis of dynamite may be effected by treating it with 

 ether or with warm alcohol, which dissolves the nitro-glycerine, and 

 the insoluble residue may be thrown on a fllter, washed, dried, and. 

 weighed. The filtrate is evaporated on a water bath till it ceases to 

 lose weight. The dynamite sold in Toronto gave by this process ; 

 Insoluble residvie 25.41, nitro-glycerine 74.59. Under the microscope 

 the insoluble residue is seen to consist chiefly of the silicious enve- 



* Moniteur Scientifique, xiii, 58. 



