84 



DR MATTHEW HAY ON THE 



glycerine, increased by the weight of the nitroglycerine known to be lost by 

 solution in the water into which it had been thrown, and which was calculated 

 from a solubility of 1 in 800, gave the total yield of nitroglycerine. The nitro- 

 glycerine before being used for any other purpose, as for analysis, was thor- 

 oughly shaken with successive quantities of distilled water until it was perfectly 

 pure. The first precipitation and washing was, I am satisfied, quite sufficient 

 to remove by far the largest part of the impurities, and the trace of these left 

 did not interfere to any noteworthy extent with the actual weight of the nitro- 

 glycerine. In certain cases I checked the weight of the raw nitroglycerine by 

 weighing the product after it had been thoroughly purified, and, again allowing 

 for loss by washing, according to the quantity of water used, I obtained almost 

 the same weights. A note of the time for which the mixture of the acids and 

 glycerine was allowed to stand before being thrown into water was always kept. 



Figure 



o'f 



Reference 



for the 

 Various 

 Products. 



Weight 



of 



Glycerine. 



Gi-ms. 



Weight of Nitric 

 Acid. 



Weight of 

 Sulphuric Acid. 



Time 



of 



Standing 



after 

 complete 

 Mixture. 



Yield of 

 Nitroglycerine. 



Strong. 

 Grms. 



Fuming. 

 Grms. 



Strong. 

 Grms. 



Fuming. 

 Grms. 



Absolute. 

 Grms. 



Percentage. 



A. 



B. 



C. 



D. 



E. 



F. 



G. 



H. 



I. 



J. 



K 



L. 



M. 



N. 



12-4 



6-1 

 10-4 



8-8 

 10-2 

 108 

 10-6 



9-4 

 10-2 



9-6 

 10-3 

 10-5 

 10-25 

 10-0 



urea, 2 grms. 



30 



25 

 30 

 30 

 30 



30 



30 

 15 



urea, 1 grm. 

 urea,r5grm. 



20 

 20 



30 

 30 

 30 

 30 



75 

 30 

 30 

 50 

 60 

 90 

 90 

 20 

 10 

 30 

 90 

 30 

 20 

 60 



20 

 30 



30 



40 



10 mins. 



8 „ 



5 „ 



5 „ 



5 „ 



5 „ 

 60 „ 

 30 „ 

 30 „ 

 30 ., 

 30 „ 

 30 „ 

 50 „ 

 30 „ 



1-7 



9-486 

 16-71 

 18-79 

 19-11 

 19-06 

 18-80 



2-89 

 23-40 

 24-50 

 23-75 

 23-40 



16-3 



107-8 

 103-8 

 175-6 

 180-2 

 202-7 

 184-3 

 30-1 

 2271 

 233-3 

 231-7 

 234-0 



The specific gravity of each nitroglycerine was taken, and was found to vary 

 from 1*601 to 1*604, depending on the temperature. From this fact alone, of 

 the close agreement in specific gravity exhibited by the various products, it 

 might be fairly concluded that they were all one and the same body. Their 

 uniformity has, however, been more certainly proved by their all having been 

 ascertained to contain the same percentage of nitrogen.* Indeed, in whatever 

 way tested, whether as regards specific gravity, yield of nitrogen and of nitrous 

 acid, and behaviour towards solvents, they were all found to agree precisely. 

 The great difference in the amounts of the various products cannot therefore be 

 regarded as being due to a difference in the nitroglycerine. It seems to be 

 almost entirely caused by the differences in the quality and proportion of the 

 * Vide TI.w and Masson's Paper on "The Elementary Composition of Nitroglycerine." 



