212 Dr. Playfoir on the NitroprussideSt 



The nitrogen in this salt was determined by Dumas' quan- 

 titative method, an air-pump being used, so as to facilitate the 

 expulsion of air from the apparatus. 



I. 7*903 grs., by Dumas' quantitative method, gave 117 CC. 

 gas; thermometer ll°'l C. ; barometer 30-415 inches. Hence 

 the nitrogen is 27*781 per cent. 



II. 4-6 grs,, also treated by Dumas' method, gave 68 CC. 

 gas ; thermometer 45° Fahr. ; barometer 30*742 inches. Per- 

 centage of nitrogen 28-79. 



100-000 100-00 100-00 100-00 100-00 



In order to estimate the water with more precision than can 

 be done in an organic analysis, a portion of salt was heated in 

 an F tube to which a chloride of calcium tube was attached : 

 9-52 grs. gave 1*20 gr. water, equal to 1*40 hydrogen per 

 cent. 



The above analyses correspond to the following calculated 

 formula: — 



724 



100-00 



It is obvious that if the analyses would authorise 25 equivs. 

 of carbon instead of 24, a very much more simple formula 

 might be given. The mean proportion of iron to carbon is 



