18 



ADULTERATED DRUG* AND CHEMICALS. 



the amount of eugenol present, it would not be wise, in view of the 

 above facts, to pronounce an oil adulterated simply because it had a 

 specific gravity below 1.045. 



Potassium cyanid 98 to 100 per cent pure has assumed considerable 

 commercial importance. In ordering this article it is customary to 

 specify the per cent of cyanid only. For financial and technical 

 reasons potassium cyanid is largely mixed with sodium cyanid. There 

 can be no real objection to this practice, if the goods are properly 

 represented, but a mixture of these two cyanids should not be deliv- 

 ered for 98 to 100 per cent potassium cyanid. In determining the 

 percentage of potassium cyanid in a mixture of this character the 

 results will be above 100 per cent in proportion to the amount of 

 sodium cyanid present. In order to meet this difficult} 7 manufacturers 

 add, or do not remove, certain inert substances, which usually consist 

 of carbonates, chlorids, or mixtures of both. 



An examination of four samples of potassium cyanid, labeled 98 to 

 100 per cent pure, gave the following results: 



Analyses of 98 to 100 per cent potassium cyanid. 



All of the above samples represent imported goods. The results 

 arc self-explanatory. No valid reason for the practice of mixing the 

 cyanids in the manner shown and selling the mixture as potassium 

 cyanid has thus far been offered by manufacturers. 



METHODS OF ESTIMATING CHLORIDS IN SOLUBLE CYANIDS. 



The present methods for detecting and estimating chlorids in the 

 soluble cyanids are not satisfactory. It is usually stated that silver 

 cyanid is soluble in concentrated nitric acid, whereas silver chlorid is 

 insoluble, but in practice it is not safe to rely on this test. The fusion 

 method is useful but dangerous. It consists in heating to redness an 

 intimate mixture of 1 gram each of the cyanid and potassium nitrate 

 and f gram- of potassium carbonate. The carbonate and nitrate must 

 be free from chlorids. In this mixture an extremely efficient oxidiz- 

 ing agent and one of the best-known reducing agents are brought 

 together. When the mixture is fused, there is a more or less vig- 

 orous chemical react ion, and frequently an explosion results. A more 

 expeditious and satisfactory method would therefore be welcome. 



The gravimetric method on the next page is based on the fact that 

 cyanid.s reduce permanganates. 



