No. 6. 



DEPARTMENT OF AGRICULTURE. 



83& 



Portion soluble in cold water,* 

 Portion insoluble after ignition 



Contalnlne:* 



Soluble lime, 



Phosphate of lime 



6.66 

 93.40 



100.00 



4.70 

 None. 



These figures show the basic super-phosphate to have ten times 

 as much matter soluble in pure cold water as the slag phosphate, 

 and may indicate the reason for slag phosphate not acting on soils 

 which are lacking in vegetable matter. Nevertheless, it will be 

 noted that there was no phosphate dissolved by the water from 

 either substance. 



The solubility in weak acid solution was as follows: 



Portion soluble in citric solution,* 

 Portion insoluble after ignition, . 



Containing* 



Soluble lime 



Soluble phosphoric acid 



Equal to phosphate of lime, .. 



Basic super-phosphate is probably made by mixing one part of 

 finely ground or slaked lime with three parts of plain super-phos- 

 phate or dissolved or acid phosphate. 



Basic super-phosphate is not unlike, in some respects, to the non- 

 acid phosphate which was manufactured in Baltimore a few years 

 ago under the Iloskin patents. 



