50 



JOURNAL OF THE 



Comments on the Result as shown in the foregoing table: 



1. As to the Water Soluble P2O3, the Washington gives higher 

 results in every case without an exception — due most likely to the 

 harder trituration, the better washing, and the absence of the rub- 

 ber-tipped pestle. But in the Atlanta some of the phosphate is pre- 

 cipitated in the flask, being washed through the filter by the first 

 washing with water and immediately precipitated — while this is not 

 the case in the Washington, and consequently this P2O5 is lost to 

 the Soluble, yet it is more than counter balanced by the gain due to 

 the trituration. 



2. In the Citrate Insoluble P2O5, the Washington gives more than 

 the Atlanta, due to three or more reasons: a. to the shorter heat- 

 ing; h. the lower temperature; and lastly, c owing to the fact that 

 no phosphate is washed through the filter by the citrate wash, and 

 so no loss takes place as in the Atlanta. While this latter is not 

 very great yet it appreciably decreases the percent. Insoluble, espe- 

 cially in the case of finely ground acid phosphates. 



3. For the Total P2O5, the Washington invariably gives higher 

 results, varying from one-half to one per cent., the fusion with 

 sodium carbonate and potassium nitrate very probably brought some 

 silica in solution, and hence possibly increased the per cent, of Total 

 P2O5. 



The Available P2O5 is larger in the Atlanta, varying from one- 

 half to two per cent., and hence will come into favor very generally 

 with the manufacturers. 



The Atlanta requires much shorter time than the Washington in 

 the manipulation — in respect to Water Soluble and Citrate Insoluble 

 but in the preliminary treatment of the Total to effect solution it was 

 found that the Atlanta using magnesium nitrate required much more 

 time than the fusion and was much more impracticable, owing to the 



