CYANAMID — MANUFACTURE, CHEMISTRY AND USES 2/ 



crease of weight was 5.46 per cent, of the original weight. The 

 failure of the two results to check more closely is due to the 

 difficulty of making accurate calcium determinations in 

 Cyanamid. 



Since the absolute quantity of calcium remains constant in 

 the mass exposed, it follows that if the absolute quantity of 

 nitrogen present do not vary, the ratio of nitrogen to calcium 

 must remain constant. Inspection of the data obtained as 

 described above shows that this is actually the case within 

 sampling and analytical limits of error. Recapitulating the 

 results by analysis and by the weights we have : 



Increase in weight Variation of nitrogen 



By Ca ratios by weighing By N/Ca ratio By weighing 



Bag A 6.32 5.46 +0-I4 +0.01 



Bag B.... 4.77 5,57 -o.io -fo.o2 



Average .. 5.54 5.51 +0.02 -f-o-oiS 



There has therefore been no loss of nitrogen under ordinary 

 factory conditions of storage, even in the case of a single 

 exposed bag, which exposes a relatively larger surface per 

 pound of material than a large pile would expose. 



Of the 5.5 per cent, increase in weight, approximately 0.7 

 per cent, is due to the addition of free moisture, 2.5 per cent, 

 to addition of carbon dioxide, and 2.3 per cent, to addition of 

 combined water; or, of the total increase in weight, about 13 

 per cent, is due to free moisture, 45 per cent, to carbon dioxide, 

 and 42 per cent, to chemically combined water. 



In the analyses given above, free moisture was determined 

 by the decrease in weight of a sample heated 5 hours at 100° 

 C, in a drying oven free of carbon dioxide. The "combined" 

 water is, properly speaking, not present as water at all, but 

 represents water which has acted hydrolytically upon calcium 

 cyanamide with the production of various organic derivatives. 

 Such hydrolyses are in the main irreversible by drying. The 

 increase in weight suffered by a sample of Cyanamid during 

 storage cannot, therefore, be determined by simply correcting 

 final analyses to the so-called "dry basis," since such a correc- 



