70 Fertilizers 



presence of phosphate at this point was known at a much 

 earlier date. 



Florida phosphates. 



The presence of phosphate in commercial quantities 

 in Florida was discovered in 1888, since which time 

 very great progress has been made in developing the 

 deposits. The deposits occur in a number of forms, 

 first, "soft phosphate," a whitish product, somewhat 

 resembling clay, and largely contaminated with it; 

 second, "pebble phosphate," consisting of hard pebbles, 

 occurring both in river beds and upon the land, and 

 mixed with other materials; and third, "rock," or "bowl- 

 der phosphate," which occurs in the form of stony masses 

 or bowlders, both large and small. These three forms 

 also differ widely in composition, both in reference to 

 their content of phosphoric acid and in respect to the 

 presence of other minerals. (See Figs. 3-5, Plates III 

 and IV.) 



The soft phosphate is the poorest in phosphoric acid. 

 It is easily prepared, and is largely used directly upon 

 the land. It is also the most variable in composition, 

 ranging from 18 to 30 per cent. The pebble rock is also 

 variable in composition, though, when washed free of 

 sand and clay, it is richer in phosphoric acid than the 

 soft variety. Good samples contain as high as 40 per 

 cent and over of phosphoric acid. The bulk of the 

 "Florida phosphate" is believed to exist in the pebble 

 form. 



The rock or bowlder phosphate, though apparently 

 much less in amount, is more uniform in composition, 

 and is much richer than either of the other forms. The 

 clean, dry bowlder phosphate often contains as high as 



