RONNA'S REPORT. 53 



" Woehler and Voelcker have made some very 

 interesting experiments on the solubility of phos- 

 phates in their dry, moist, and gelatinous state, 

 on the solubility of bone-meal, of boiled bone, 

 of glue refuse, of guano, of coprolites, of phos- 

 phorite, and of apatite, all of which prove the 

 beneficial effect which the mechanical condition 

 of phosphates exercises upon their solubility. 

 Thus precipitated phosphate of lime, slightly 

 moistened and allowed to remain in contact 

 with water for a week, lost 1.10 gramme, while 

 Suffolk coprolites lost but 0.09 gramme, and 

 Cambridge coprolites, 0.08 gramme. The amount 

 of water used in either case was 100 litres. In 

 a solution of ammoniacal salts, in the proportion 

 of 1 to 100, precipitated phosphate of lime lost 

 4.80 grammes, Suffolk coprolites, 0.24 gramme, 

 and Cambridge coprolites, 0.33 gramme. A 

 solution containing 1 per cent, of carbonate of 

 ammonia, dissolved of precipitated phosphate of 

 lime 2.48 grammes, of coprolites 0.36 gramme. 

 Precipitated phosphate of lime afforded to a 

 solution, containing 1 per cent, of sea-salt, 0.97 

 gramme; coprolites 0.19 gramme. 



" But more than all the experiments in the 

 laboratory, those of the practical agriculturist 

 have confirmed the necessity of phosphates 

 rendered soluble, and these are the experiments 

 of twenty years, and of a whole country which 



