PHOSPHATES AND NITROGEN 37 



lose a part of its weight and become friable and per- 

 fectly white. Well, this bone, calcined in the fire 

 for a long time, is composed chiefly of phosphate of 

 lime. It contains phosphorus, the most combustible 

 of substances, and yet is itself absolutely incombusti- 

 ble ; it contains one of the most poisonous substances, 

 and yet is itself quite harmless ; into its composition 

 there has entered an ingredient possessing atrocious 

 acidity, and yet the compound itself has no taste. 

 Similarly combined and equally harmless, phos- 

 phorus is found in meat, milk, cereals, in flour and 

 bread. 



"A cow can furnish each week about 70 liters of 

 milk containing 460 grams of phosphate. This phos- 

 phate comes from hay, which obtains it from the soil. 

 But as the soil contains only a moderate quantity of 

 it, and the hay continually takes it away, the supply 

 will at last become exhausted and the milk will be- 

 come poorer and less abundant. If a kilogram of 

 powdered bones, containing about the same quantity 

 of phosphate as the 70 liters of milk, is spread over 

 the pasture, it will make good the weekly loss in 

 phosphate that the soil undergoes in the production 

 of the cow's milk. Hence the efficacy of powdered 

 bones on exhausted pasture land. 



"Phosphoric acid combined with other substances 

 is found in all our agricultural products, and hence 

 the phosphate from bones has a very marked effect 

 on our crops. Harvests have been doubled as if by 

 magic through the use of powdered bones. A kilo- 

 gram of this powder contains enough phosphoric 



