10 JOURNAL OF THE 



was chosen, of which tvvo grams were dissolved in nitric acid 

 and hydrochloric acid, and the total phosphoric acid found to be 

 14.56 percent. Another two grams were then ignited for about 

 the same length of time that it requires to incinerate two grams 

 of a cotton seed meal fertilizer to complete ash, and then dis- 

 solved in nitric acid. The determinations were parallel, so that 

 each received the same amount of heating with acid, which was 

 protracted. In the case of the ignited phosphate, undissolved 

 portions w^ere plainly manifest to the eye, and the percentage 

 found w^as only 13.62. The undissolved portions were filtered 

 out and readily yielded to hydrocliloric acid, giving fulsome pre- 

 cipitate of phosphoric acid. Next, another two grams w^cre 

 ignited and dissolved in hydrochloric acid, when the full content 

 of phosphoric acid was readily yielded. Hence, it is concluded 

 that had hydrochloric acid been used to dissolve the six inciner- 

 ated fertilizers employed in the above experiments, higher per- 

 centages would in all probability have been found. Fusion 

 would have furnished an absolutely certain means of arriving at 

 the undoubted maximum content of phosphoric acid, but time 

 was limited and simple incineration was resorted to on account 

 of expedition ; and solution in nitric acid instead of hydrochloric 

 acid was employed after incineration because, as the results were 

 to be compared, it was advisable to employ the same solvent 

 power in each case. 



In addition to the six experiments described above attention 

 is called to the following: Two saniples of cotton seed fertilizers 

 were procured in which another chemist had made determinations 

 of ^o^a^ phosphoric by the nitric acid method. His totals were 

 9.13 and 9.33. I found bv incineration and solution in hvdro- 

 chloric acid 9.85 and 10.13, a difference of 0.72 per cent, and 

 0.80 per cent, respectively. Taking his own determinations of 

 insoluble^ the available by his analysis was 0.72 percent, short in 

 the first instance (7.40 per cent, when it should have been 8.12 

 per cent.), and 0.80 per cent, short in the second instance (7.50 

 when it should have been 8.30 per cent.). The disparity here is 

 excessive, but the fault is not due to the chemist but to the 



