S()i.rr.iLiT\ oi- I'liosiMioK.u oxini:. 207 



Calculated amount. Percentage fomul after Sliakin;^. 



17.78 per cent. -20.23 per cent. 



In order to contirni tlie abti\e. the t()]]()\vin<,r mixtures were 

 iiKule : 



A. A medium liiyh-orade suporphosi)hate and bone ash 

 containing^ i5-'^'3 pt^r cent, and 0.73 per cent, of water- 

 soluble phosphoric oxide respectively. 



B. A high-grade superphosphate and bone ash on- 

 taining 18.25 per cent, and 0.O5 per cent, of water-solul)le 

 phosphoric oxide resi)ectively. 



The results of the analyses being: — 

 No. Original 3 24 1234 



Mixture hotirs. hours, week, weeks, weeks, weeks. 



A. 8.18 9.65 9.39 8.89 8.66 8.86 8.80 



B. 9.45 10.04 9.94 _ _ _ — 



This once more proves that an increase of water- 

 soluble phosphoric oxide residts when superphosphate and bone 

 ash are mixed. 



In order to confirm the above results, and ascertain if there 

 would be such an increase when weighed quantities of calcium 

 phosphate of different origin are extracted with a water-solution 

 of superphosphate, the following quantities were taken : 

 .\. 4.366 grams of pure calcium phosphate. 



B. 4.366 grams of bone ash. 



C. 4.366 grams of precipitated calcium phosphate. 



These were all treated in the same manner, the quantity 

 being extracted for half an hour in a shaking machine with 500 

 c.c. of superphosphate solution, then tiltered, and in an aliquot 

 part the water-soluble phosphoric oxide was determined, the 

 results being : — 



Theoretical Amount of Water- Percentage of Water-Soluble 



.Soluble Phosphoric Oxide. Phosphoric Oxide found. 



No. 



A. 16.81 per cent. 17-59 per cent.* 



B. 16.83 per cent. 17.82 per cent. 



C. 16.93 per cent. 17.89 per cent. 



In the first column the figure given is the calculated 

 amount of water-soluble phosphoric oxide in a mixture of 100 

 grams of superphosphate and 8.732 grams of the calcium phos- 

 phate, and in the second column the percentage of water-soluble 



*This result was obtained I)}- extracting the 4-366 grams with 500 c.c. 

 of superphosphate solution, as already described, taking an aliquot part 

 (equivalent to 2 grams) for analysis. The determuiation was repeated a 

 second and third time with similar quantities of material, viz., 4.366 grams 

 of calcium phosphate were extracted with 500 c.c. of superphosphate 

 solution, but the mixture was diluted to 1,000 c.c; larger aliquot parts, 

 corresponding to a 2l- grams and a i gram quantity respectively were 

 taken for analysis, and gave 17 06 per cent, and 17.87 per cent, of water- 

 soluble phosphoric oxide. 



