Phosphates Their Sources 71 



40 per cent phosphoric acid, far exceeding in richness 

 the South Carolina rock superphosphate. 



Canadian apatite. 



This material is a crystallized rock of true mineral 

 origin, and occurs associated to a greater or less extent 

 with other materials. It is, therefore, not uniform in 

 character, the phosphoric acid varying according to 

 the amount of the other substances present. 



It is mined in the provinces of Quebec and Ontario, 

 and separated into various grades at the mines. The 

 mining is expensive, and the necessity for grading in 

 addition makes the cost of production proportionately 

 high. The highest grade of this phosphate is very pure, 

 containing 40 per cent of phosphoric acid. 



Tennessee phosphate. 



The phosphate deposits in Tennessee were discov- 

 ered in November, 1894, since which time they have 

 been exploited and a rapid development made. This 

 phosphate differs from the phosphate of South Carolina 

 and Florida in that it does not exist as nodules, pebbles 

 or bowlders, but in veins and pockets, and, therefore, 

 does not need to be washed and dried previous to its 

 treatment. While the phosphates from the various de- 

 posits are not uniform in their composition, it is possible 

 to secure large quantities that equal or exceed 30 to 32 

 per cent of phosphoric acid, or 70 per cent or over of 

 bone phosphate, and that are relatively free from dele- 

 terious substances, thus making them not only a rich 

 but a valuable source of supply for the manufacturers of 

 superphosphates. 



