1889.] PUBLIC DOCUMENT — No. 4. 591 



The phosphoric acid present is neither to any extent soluble 

 in water nor in a solution of citrate of ammonia. The com- 

 position of the slag is peculiar, on account of an excess of 

 caustic lime, which favors a breaking up into minute particles 

 when exposed to air and moisture. The more finely ground 

 when exposed to atmospheric influences, the more rapidly 

 takes place a general disintegration. This behavior tends to 

 difiuse the phosphoric acid, and favors absorption by the 

 roots. No previous treatment by acids has been found 

 necessary to secure satisfactory returns when used as a phos- 

 phoric acid source for plant growth. On account of the 

 alkaline reaction of the " phosphate meal," no ammonia salts 

 or organic nitrogen compounds are used as an admixture for 

 the production of more complete fertilizers. In case nitro- 

 gen shall be applied, nitrate of soda is used, to furnish that 

 element. Muriate of potash and kainite are recommended as 

 potash sources. 



European agricultural chemists speak well of this new 

 source of phosphoric acid. As it is claimed that phosphoric 

 acid can be furnished at less cost and more efficiently in the 

 form of " phosphate meal " than in any of our known mineral 

 resources of insoluble phosphoric acid, it seems desirable 

 that experiments should be instituted to test its merits. 



Fifteen dollars per 2,000 pounds has been asked in our 

 vicinity for a finely ground material. 



Concentrated Flower Food. 



[Sent on from Springfield, Mass.] 



Per cent. 



Moisture at 100° C, . 11.20 



Ash, 42.89 



Phosplioric acid, 6.30 



Sulphuric acid, 15.73 



Potassium oxide, 4.72 



Sodium oxide, 17.45 



Calcium oxide, 6.18 



Nitrogen in organic matter, 2.31 



Nitrogen in nitrates, 4.66 



Insoluble matter, .25 



