TJie Phosphates of America. 11 3 



all they ask of us is the maximum of " available phosphoric 

 acid" in a fine, dry and merchantable condition, and this we can 

 give them without difficulty and without regard to a few units 

 more or less of oxides of iron and alumina, by carefully regulat- 

 ing the percentage of carbonate of lime in our raw product. When 

 circumstances allow of this regulation, through the mixture of a 

 phosphate containing much carbonate, with another containing little 

 or none as for instance, the blending of Canadian apatite with 

 Belgian cretaceous phosphates we personally prefer that course, 

 but where such facilities are wanting, we invariably resort to the 

 addition of finely powdered chalk, or any other cheap and available 

 source of the carbonate. 



This method of facilitating spontaneous drying was suggested 

 by us to a few manufacturers some years ago, and has been depre- 

 cated and denounced as far too costly for general use. Those who 

 denounced it, however, have not yet made known a cheaper or more 

 practical plan, for the one which they proposed, of effecting the 

 drying by the application of external heat in ovens or on hot floors, 

 has invariably proved disastrous. How could it in fact do other- 

 wise, when we know that monocalcic or water-soluble phosphate 

 of lime cannot exist in any other than the hyd rated state? 



In making our proposal, we had borne in mind that this hydrated 

 state can only be preserved by spontaneous drying, and we had 

 experimented enough to know that this drying can only be easily 

 effected as we have described. We consequently can see no more 

 valid reason to-day than we could ten years^ago, why, under proper 

 restrictions, the carbonate should not be used. 



The difficulties of a manufacturer only commence when he is 

 called upon to use a refractory raw material, and it is only under 

 such circumstances that he finds scope to develop the fertility of 

 his resources. If our mineral phosphates were not of ever-varying 

 composition, a knowledge of chemistry would not be so essential 

 to their treatment, but as the case stands we are helpless without 

 the assistance of the analyst. In his absence the manufacturer 

 gropes blindly in the dark, for he knows not what elements he is 

 mixing together and can predict nothing concerning the nature of 

 the compound that will result from their reactions on each other. 



Figures, like actions, are more eloquent than words, and as our 

 assertions are made on the strength of our own work, we will close 

 this part of our argument by giving some examples that should 

 carry conviction. 



