MANURED LW 



the resulting solution run out into great tanks to cool arid 

 crystallise. The nitrate crystals which form are removed, 

 freed from the mother liquor by a slight washing and 

 spread out in the sun to dry. The salt is then ready 

 for putting into bags for shipment to the various markets 

 of the world. The exportation of nitrate of soda from 

 Chili began about the year 1830. In 1840 the quantity 

 exported amounted to about 14,000 tons ; by 1870 

 it had increased to about 200,000 tons ; in 1880 it was 

 400,000 tons; during the season 1905-1906 it exceeded 

 1,500,000 tons. 



The composition of the stuff as it leaves the works 

 averages between 96 and 97 % nitrate with some 2 % 

 water and traces of chlorides, sulphates and insoluble 

 matters. Unless deliberately adulterated or allowed to get 

 wet it seldom falls belo\v the guaranteed 95 % . The only 

 really harmful impurity likely to be found in the manure 

 is perchlorate. Recent experiments go to show that nitrate 

 containing more than a mere trace of this salt may do 

 damage to crops to which it is applied, but the exact 

 amount that must be present before any appreciable effect 

 is produced is still a matter of doubt. 



, f 'harar-tei' at* a manure. Nitrate of soda guaranteed 95% 

 pure contains rather more than 15 ^% nitrogen and is, 

 next to sulphate of ammonia, the most concentrated form 

 of nitrogen at present used as a manure. It is usually 

 the cheapest form of nitrogen on the market, and its price 

 is utilised in valuing the nitrogen of other manures. 



The character of the salt, /. e. its ready solubility and 

 the ease with which it diffuses in solution, together with 



