146 THE ROYAL SOCIETY OF CANADA 



in this latter mix is greater than in the 1 to 1 mix, the percentage 

 rendered available is less, viz. 71-4 per cent. 



Considering the results obtained by the A.O.A.C. methods, it 

 will be observed that while the percentages of water soluble phosphoric 

 acid do not differ greatly from the water soluble data just discussed, 

 the percentages of "citrate soluble" are very much less than when 1 

 per cent citric acid solution is used. This markedly reduces the total 

 percentages of available phosphoric acid, as compared with the results 

 when employing the citric acid solution. In the mix 1 to 1, the total 

 available phosphoric acid is 6-81 per cent, of which 6-00 per cent is 

 soluble in water. 



Wet Mix: Three series were experimented with, the proportion 

 being 



The percentage of water soluble phosphoric acid in all three 

 series was practically the same by both methods, but as the case of 

 the dry mix the citric soluble percentages are much higher than those 

 obtained by the A.O.A.C. citrate soluble method. 



The best results were obtained with proportions of series (c) 

 6 N.C. : 6 F.P.P. : 1 H2O which gave a product containing 16-09 per 

 cent<available phosphoric acid (of which 7 • 66 per cent was water soluble), 

 as determined by 1 per cent citric acid solvent. Since the total 

 phosphoric acid in the mix is 16-0 per cent, it is evident that the con- 

 version is very satisfactory. Similarly in series (a) 100 per cent 

 conversion was brought about, but the product contains a lower 

 percentage of available phosphoric acid (10-51), corresponding to 

 the lower percentage of total phosphoric acid in the original mix. 



By the A.O.A.C. methods, series (c) similarly possessed the 

 highest percentage of available phosphoric acid, viz. 9-26, which 

 stated otherwise means that practically 60 per cent of the total phos- 

 phoric acid in the mix had been rendered available. 



Table II.— Canadian Apatite 



Dry Mix: It will be first evident that the degree of conversion 

 is decidedly lower than in the similar series using Florida Pebble 

 Phosphate, indicating the harder and more resistant nature of the 

 Canadian Apatite. 



The series in which the proportions were 1 N.C. to 1 C.A. proved, 

 as in the case of the Florida Pebble Phosphate, the most successful. 

 Its product contained 8-43 per cent available phosphoric acid (of 



