10 



Preparation of Substances 



in colum (6). It is noticeable that many 

 of the constituents vary widely in quantity. 



Moisture and organic matter 



Phosphate of lime, Ca3P20s 



Phosphates of iron and aluminium 



FeP04, AIPO4 



Carbonate of lime, CaCOa 



Carbonate of magnesia, MgCOa . . . 



Fluorid of lime, CaF2 



Iron pyrites, FeS2 



Iron oxid, Fe203 



Alumina, AI2O 



Sand and silicious matter 



(&) 



Per cent 



1.00 

 55.00 



6.50 

 3.50 

 0.75 

 2.25 



28.00 

 100.00 



The natural soiu"ces of phosphorus are 

 the mineral apatite, or phosphorite, which is 

 an ingredient of nearly all soils. It has the 

 same formula as the raw rock phosphate but 

 is entirely different in appearance. Immense 

 deposits of this mineral are localized in 

 Quebec and Ontario, Canada. 



QUESTIONS 

 (To be answerd in the notebook.) 



1. What is the per cent of P2O5 in calcium dihy- 

 drogen phosphate? 



2. Supposing equation (2) to represent all that 

 happens when sulfuric acid acts upon rock phosphate, 

 calculate the per cent of hydrated acid phosphate and 



^he per cent of hydrated calcium sulfate in the 

 mixture. 



