NITROGENOUS MANURES 93 



charge of crude salt. The muds from the clari- 

 fication are treated in the same way. 



Nitrate of soda is marketed in the original 

 sacks weighing 254 to 308 Ib. It forms a mix- 

 ture of crystals of different sizes. It draws mois- 

 ture from the air and when it \s preserved in 

 sacks they rot after some time and tear with 

 the slightest pull. When the sacks are emptied, 

 one part of the material, always moist, remains 

 adherent to the fabric, from which there results 

 not only a loss of matter, but also a less of sacks, 

 as these gunny bags then become unutilizable. 



Nitrate of soda is often colored yellow by the 

 presence of chromate of potash or violet by the 

 presence of nitrate of manganese. The presence 

 of nitrate of potash or magnesium chloride renders 

 it deliquescent, hence arises loss by the drainage 

 of dissolved nitrate; that is why the bags are 

 lodged on beds of plaster or clay which absorb 

 the liquid. But it is best to spread the nitrate 

 intended for mixing in a not too warm place. 

 The bags are washed with tepid water, and the 

 solution is added in the manufacture of super- 

 phosphate which has to be mixed with nitrate, 

 or it is concentrated in a pan. Certain manufac- 

 turers content themselves with beating the bags 

 free from the adherent salt. If the nitrate ought 

 to be employed alone it is screened and the lumps 

 crushed in a disintegrator, or in the toothed 

 roll crusher. It is dried in the old phosphate 

 drier. However, if it be stored for a certain time 



