150 Agricultural Chemistry. 



cent of potash. It is generally too .expensive to use for manurial 

 purposes, as it is used very extensively in various manufacturing 

 processes. 



Calcium nitrate. This product is manufactured by passing 

 strong electric discharges through air. By this means oxides 

 of nitrogen are produced by the union of oxygen and nitrogen. 

 These gases are absorbed in water with the production of nitric 

 acid. This acid is then led into milk of. lime, which results in 

 the formation of calcium nitrate. The product is next concen- 

 trated until it solidifies as a material containing about 13 per cent 

 of nitrogen. At the present time it is almost entirely produced 

 in Norway, where cheap water power is available, and in cheap- 

 ness compares favorably with nitrate of soda. As a fertilizer 

 and as a source of nitrogen it has given excellent results. 



Calcium cyanamide is a comparatively now nitrogen-contain- 

 ing fertilizer and is produced by heating calcium carbide in a 

 current of air from which the oxygen has been removed. When 

 used as a manure it has in many cases given as good results as 

 the same amount of nitrogen applied as nitrate of soda or am- 

 monium sulphate. Because of its injurious effect on germinat- 

 ing seeds, it should be incorporated with the soil a week or so 

 before any seed is sown. It contains about 20 per cent of niti 

 gen, and is to-day produced in limited quantities in this counti 



Organic nitrogenous materials. In order to bring out cleai 

 the relative value of this class of fertilizing materials they 

 be discussed under the following heads; ; first, those materials 

 which the nitrogen becomes readily available in a comparative 

 short time by decomposition in the soil; second, those materii 

 which undergo fermentation very slowly and the nitrogen 

 which only becomes available after a long time. Readily avi 

 able materials include such products as dried blood, meat sera] 

 tankage, dried fish or fish scrap, cotton-seed meal and cast 

 pomace. 



Dried blood. This material is obtained by drying the bl< 

 from shi lighter houses. Two grades are found on the market, I 



