42 JOURNAL OF THE 



For my samples I selected, first, a good specimen of ground 

 bone, containing 40.01 per cent, phosphate of lime and 54.02 

 per cent, volatile-and-organic matter, and ground fine enough to 

 pass a 60-mesh sieve. Next, I chose an especially pulverulent 

 sample of South Carolina phosphate "floats," and then selected 

 some good fish-scrap, ground to pass a 40-mesh sieve, and some 

 excellent specimens of cotton seed meal, dried blood, and "am- 

 monite," all ground to pass a 60-mesh sieve. In all these sam- 

 ples I determined the per cent, of phosphate of lime and of 

 volatile-and-organic matter. I then made four mixtures, con- 

 sisting of fish-scrap and floats, cotton seed meal and floats, dried 

 blood and floats and ammonite and floats, in such proportions by 

 calculation that the content of volatile-and-organic matter in 

 each should be the same as in the ground bone, namely, 54.02 

 per cent. 



I then took 25 grammes of the ground bone and 25 grammes 

 of each of the four mixtures, rubbed them up well with water 

 in mortars, and transferred them to filters in funnels, let the 

 water extract filter through, and then washed the contents of the 

 filters with successive portions of water until my filtrates 

 amounted to, I think, about a liter each. I then stopped the 

 ends of the funnels with little stoppers and left the moist con- 

 tents to rot at the ordinary temperature of the laboratory, w ith 

 free access of air. During the process of the decomposition I 

 kept the masses moist by additions of water from time to time, 

 and, by stirring them, kept fresh portions turned up and exposed 



to the air. 



I found the per cents, of soluble phosphoric acid in my fine 

 samples, just after mixing and before rotting (obtained in the 

 filtrates just alluded to), to be: 



TABLE I — BEFORE ROTTING. 



1. Bone meal 0.1149 per cent. Soluble P2O5. 



2. Fish and floats 0.1292 



3. Meal and floats 0.0486 " 



4. Blood and floats 0.0289 *' 



5. Ammonite and floats 0.1537 



