1908.] Experiments with Calcium Cyanamide. 655 



Other experiments on these lines were made, in which the 

 exposed cyanamide was dried in a current of air that was 

 afterwards passed through acid to absorb any ammonia 

 volatilised ; they confirm the results set out above and show 

 that the action in the first week is almost wholly a slaking of the 

 free lime attended by a slight production of ammonia which 

 is only volatilised as long as the material remains dry. After 

 the slaking is complete the material begins to get damp and 

 may form a cake ; in these later stages larger quantities of free 

 ammonia are produced but only volatilise on drying. 



It should be borne in mind that these are extreme cases and 

 that changes of the magnitude of those taking place in the first 

 week would only occur in a manure store after a very long 

 time, so slowly would moisture reach the material inside the 

 bags. It is well known that ground quicklime itself can be 

 stored in bags for some time without serious change. To 

 determine the extent of the change taking place in practice, 

 bags containing 56 lb. each of cyanamide, sulphate of ammonia 

 and nitrate of soda were placed on the floor of the manure 

 shed on 1st August and weighed again on 24th August and 

 14th October. 



Aug. 1st Aug. 24th Oct 14th 



Lb. Lb. Lb. 



Cyanamide 56 ... 57I ... 58I 



Sulphate of ammonia ... 56 ... 565 ... 57! 

 Nitrate of soda ... • ... 56 ... 55! ... 54J 



On 24th August the cyanamide was powdery and in good 

 condition, by 14th October one corner of the bag had burst 

 owing to swelling from the slaking of the lime ; the total gain 

 of weight, however, is only 2f- lb., or about 5 percent; Now, as 

 under conditions of maximum exposure and complete slaking 

 a gain of 67 per cent, of moisture had only been attended by a 

 loss of 0-37 per cent, of nitrogen, the loss of ammonia when 

 the cyanamide had been stored in a bag and had only gained 

 5 per cent, in weight would be imperceptible, since we may 

 assume that the loss will be in proportion to the extent of 

 slaking. That the atmosphere of the manure shed had been 

 damp is shown from the fact that the sulphate of ammonia 

 had also gained in weight and caked a little, while the bag of 

 nitrate of soda had become soaking wet, so that the floor 



