282 State Board of Agkioultuke, &c. 



salts yearly upon the market, and from tliis apparently unlim- 

 ited source both agriculture and the arts can hope for an 

 abundant supply. Already these Stassfurt salts are going 

 wherever advanced agriculture demands them. 



Phosphorus Compounds. — The supply of phosphorus 

 compounds used to come almost wholly from the bones of 

 animals, and these continue to be a great source. So the 

 bones of domestic animals are gathered up to meet the demands 

 of commerce Bat t'lis supply is quite too limitel and the 

 bones of other than domestic animals are souo;ht for. The 

 prairies of Kansas and the West are gleaned over for the 

 buffalo bones that have been accumulating upon them ; and 

 it is said that battle fields have been explored and the relics 

 of human victims have been called upon to do humanity a 

 further service. 



But the bones of animals of whatever sort tail to con- 

 tribute enough fertilizing material for the demands of an 

 advancing agriculture. Supplies haffe been sought from the 

 rocks with success. The fossil excrements of extinct rep- 

 tiles — coprolites as called by tlie geologist — have been found 

 a source of commercial wealth so that the privies of old 

 time animals have been cleaned out in the interests of agri- 

 culture. 



Still greater sources of phosphoric acid have been 

 demanded and the demand has been met by the discovery 

 of what promises to be an inexhaustible supply. Phos- 

 phorite, calcium phosphate confined to no particular geo- 

 logical formation, appearing now low down and now high 

 up in the stratified rocks, has been discovered in many 

 places and in many countries. In our own country the deposits 



