272 CHEMICAL MANUEES. 



the molasses season, 25 to 30 kg. (55 to 66 lb.) of sulphate of am- 

 monia were obtained per hectoUtre of alcohol, and it has been found 

 that in the distilling column an appreciable amount of glycerine 

 perfectly recoverable is also separated. In treating spent wash by 

 fermentation, almost all the organic matters, including the nitro- 

 genous matter, are decomposed. The spent wash from 370 kg. (814 

 lb.) of molasses, the appioximative quantity to produce 1 hectolitre 

 (22 gallons) of alcohol, yields besides ammonia about 35 kg. (77 lb.) 

 of volatile fatty acids. The acids which pass over on distillation are 

 white and fiee from impurities. The distillery industry could furnish 

 enormous quantities, and it would be desirable for the trade to find 

 new outlets for them. 



The Mamifacture of Cyanamide and of Nitrate of Lime. — 

 Atmospheric air is an inexhaustible source of nitrogen. It is calcu- 

 lated that the column of air which covers a hectare (2*47 acres) of 

 ground contains about 79,000,000 kg. of nitrogen (say 79,000 

 metric tons, which gives 31,600,000 metric tons per acre), equal to 

 500,000,000 kg. of nitrate of soda (say 50,000 metric tons per hectare 

 or 20,000 tons per acre). But nitrogen exists in the free state in the 

 air, and to render it assimilable by plants, it is necessary to convert 

 it into appropriate compounds. We know that this conversion can 

 be effected by certain bacteria of the soil (leguminous bacteria, etc.), 

 likewise by certain phenomena which occur in nature, such as- 

 electrical discharges, especially lightning. But the amount of nitro- 

 gen brought into the soil in this way is far from being sufficient to 

 cover the requirements of plants, and vigorous efforts are now bemg 

 made to capture atmospherical nitrogen under an assimilable form. 

 Experiments made enable us to affirm that such is possible. But 

 all the tentatives made in this direction show that the industiial 

 fixing of atmospheric nitrogen requires the use of great quantities 

 of electrical energy. There are at present two chief methods of 

 manufacture : (1) the Frank and Caro process, (2) the Birkeland and 

 Eyde process. The first consists in combining atmospheric nitrogen 

 dry and deprived of its oxygen with calcium carbide, obtained by 

 fusion in the electrical furnace of equal amounts of coal and lime. 

 The product so obtained is termed lime nitrogen or cyanamide of 

 calcium. The second process consists in oxidizing atmospheric 

 nitrogen by electrical means, and converting it into nitric acid,, 

 which is put into commerce as nitrate of lime with 13 per cent of 

 nitrogen, which has the greater analogy with nitrate of soda and 

 which like the latter is assimilable by plants. The two products 

 come on the market as more or less dark dirty grey powders. 

 Their percentage of nitrogen varies from 13 to 21 per cent. The 

 following are the analyses given by Cirandeau : — 



