130 SOOT COAL ASH 



The following analyses l will illustrate some of these points : 



Further analyses of domestic soot gave 



According to these investigations, about 96 per cent of the nitrogen 

 in soot is present as ammonium salts, though some could be detected 

 in the form of pyridine bases. Light, bulky soot is always richer in 

 nitrogen than the denser varieties and therefore more valuable for 

 manurial purposes. A good sample ought not to weigh more than 

 28 Ib. per bushel. 



Coal ash. As a rule the ash of coal is comparatively poor in 

 manurial ingredients, and though, on some soils, coal ash may with 

 advantage be used, it probably acts mainly by its influence on the 

 porosity and other physical properties of the soil rather than as a true 

 manure. The usual proportion of phosphorus pentoxide in the ash of 

 coal appears to be about 1 per cent and rarely exceeds 1'5 per cent, 

 but the author found, in the ash of a coal from Witbank in the Trans- 

 vaal, 5 '5 per cent. Only one other similar instance has been recorded, 

 so far as the author can ascertain, and that was in the case of the ash 



Cohen and Ruston, Jour. Soc. Chem. Ind., 1911. 



