138 The Phosphates of America. 



CHAPTER VIII. 



SELECTED METHODS OF PHOSPHATE ANALYSIS AND GENER- 

 ALLY USEFUL LABORATORY DETAILS. 



THE world's consumption of mineral phosphates and superphos- 

 phates from all sources, amounts to several million tons a year. 

 The commercial value, alike of these natural and artificial products, 

 depends upon their percentage of phosphoric acid, and upon their 

 freedom from certain undesirable or injurious constituents as re- 

 v e aled by chemical analysis. 



The miner, the manufacturer, and the farmer, are hence equally 

 dependent upon the analytical chemist, whose province it is to 

 determine how much the two first shall receive, and how much the 

 last shall pay for the merchandise. The responsibility is a heavy 

 one for the analyst, and he must either justify it or bring a great 

 deal of discredit upon his profession. 



We know that chemistry is the most precise of the sciences. 

 It is not only capable of producing exact results, but it can fore- 

 tell with unerring certainty, even before an operation is commenced, 

 what those results will be. Complete concordance in phosphate 

 analysis should consequently be " a thing of course," and a dozen 

 chemists in as many different parts of the globe have no right to 

 differ in the second decimal in their findings on the same sample. 



An average error of no greater importance than say one unit 

 of phosphate of lime, worth 20 cents, would entail, when spread over 

 a total year's consumption of raw material, a cash difference of 

 about $300,000. This difference, of course, constitutes a loss, 

 which is sometimes borne by the miners who sell, and sometimes 

 by the manufacturers who buy. 



We have seen that in certain cases where superphosphates are 

 sold on the basis of their water-soluble phosphoric acid, iron and 

 alumina phosphates as a raw material, have no commercial value. 

 Any widely differing results obtained by chemists in their deter- 

 minations of these bodies in shipments of mineral phosphates, 

 therefore, may cause infinite trouble between miners and manu- 

 facturers. 



At the present time there prevails between the contracting 



