144 The Phosphates of America. 



agreed upon for safe-keeping in case of dispute ; the other two are 

 taken, one by each of the contracting parties, for the purposes of 

 analysis. 



ANALYSIS OF MINERAL PHOSPHATES APATITE, PHOSPHORITE, 



COPROLITE, ETC. 



The sample must bear the date upon which it was drawn, and 

 must in every case be representative of the bulk. It must be clearly 

 labelled with all particulars as to its origin and destination, includ- 

 ing the name of the vessel or the number of the railroad car. When 

 drawn as a working sample of the mine it must bear the mention 



"average sample from Mine No drawn by from 



piles No representing tons." 



All these details are entered in the laboratory journal, and this 

 having been done, the entire sample to be analyzed is first made to 

 pass through a screen of 80 mesh by the analyst. The following 

 determinations are then proceeded with : 



Moisture. 



Water of combination and organic matter. 



Carbonic anhydride (CO 2 ). 



Insoluble siliceous matters. 



Phosphoric anhydride (P 2 O 5 ). 



Sulphuric anhydride (SO 3 ). 



Fluorine (Fl). 



Lime (CaO). 



Magnesia (MgO). . 



Iron and alumina as oxides (combined). 



Moisture. 



Two grammes of the substance are very carefully weighed in 

 accurately tared and well-ground watch-glasses. The latter are 

 then adjusted with the clip so as to leave a sufficient opening 

 for the passage of steam, and are placed in the gas-oven at 110 

 C. At the end of three hours the glasses are taken out, closed 

 tightly, placed in the desiccator until quite cold, and then brought 

 upon the scale. 



The difference between the present and the original weight 

 4- 2 = moisture in one gramme of the material. 



Water of Combination and Organic Matter. 

 The residue from the moisture determination is carefully brushed 

 into an accurately-tared platinum crucible. The crucible is placed 



