292 ANNUAL REPOKT SMITHSONIAN INSTITUTION, 1908. 



of 13.7 i3er cent of the total consumption, while saxonite, a nitro- 

 glycerin explosive, ranks first, with 22.18 per cent of the total. 



Am I therefore right in saying that we have succeeded in making 

 the use of explosives in coal mines infinitely more safe than before, 

 but that we do not really know why ? . 



IV. 



Nitrocellulose has found a greater sphere of use for purposes 

 other than smokeless powder or dynamites. The celluloid industry, 

 introduced by the Brothers Hyatt, and more recently the artificial 

 silk industry, consume enormous quantities. Of celluloid the United 

 States produce about 4,000 tons per annum, Germany 15,000, and 

 the rest of the world about 5,000 tons, of which yearly total of 24,000 

 tons this country produces about 2 per cent. This necessitates about 

 14,000 tons of nitrocellulose per annum. Of artificial silk, about 

 6,000 tons are made annually, though only about 200 tons in Eng- 

 land." The amounts used for varnishes like pegamoid, fabrikoid, 

 etc., for making or steeping incandescent gas mantles, for water- 

 proofing solutions, for patent leather (nitrocellulose dissolved in 

 amylacetate, and mixed with aniline black) and for photography 

 are also considerable. The solubility of the nitrocellulose in a definite 

 mixture of ether alcohol to the extent of 2 per cent either way is by 

 no means unimportant, as this may mean 10 per cent more of very 

 expensive solvent. When you consider that one of these factories, 

 which I had occasion to revisit quite recently, makes as much as 3,000 

 kilograms of silk a da3^ you will have some idea of the sums involved. 



In neither of these cases is the nitrocellulose pulped, but the whole 

 of the fiber is dissolved. I am afraid purification is sometimes not 

 carried as far as it ought to be with due regard to the stability of the 

 finished celluloid. In the case of artificial silk the fact that the 

 nitrocellulose is denitrated seems to indicate that thorough purifica- 

 tion is unnecessary, but the silk fiber made from well-stabilized nitro- 

 cellulose will be found to possess inherent good properties of its own. 

 The same may be said of varnish, although in this case a slight 

 acidity at certain stages of the process has the advantage of rendering 

 the nitrocellulose more readily soluble. 



The manufacture of these nitrocelluloses also varies in other re- 

 spects. In dealing with such large quantities everything is carried 

 out expeditiously and without much handling. The nitrocellulose for 



<* According to Dr. Ricliard i^chwarz, there are at present in Europe 30 fac- 

 tories making artificial sillv, and the world's production in 1907 amounted to 

 3,300,000 kilograms, of which 1,500,000 were nitrocellulose silk, 1,300,000 

 " Glanzstoff," and 500,000 viscose silk (Neue Freie Presse, Vienna, January 

 5, 1909). 



