ELIBHA MITCHELL SCIENTIFIC SOCIETY. 43 



In seventeen days the n)ass of moist bone meal was thor- 

 on«;lilv rotted, and a week later the other mixtures showed that 

 they, too, were well decomposed throughout. The putrid smell 

 from each of the five was highly offensive — alipost unbearable. 

 I now leached out the soluble again with the same amount of 

 water as at fir.>t. The filtration was exceedingly slow, requiring 

 about six davs, so slowlv did the successive additions of water 

 percolate through the putrid masses. 



In my filtrates I determined the soluble phosphoric acid as 

 before, and found it to be as follows: 



'J'ABLE II AFTER ROTTING. 



1. Bone meal 0.0G.34 per cent. Soluble PaOs. 



2. Fish and floats 0.0894 " " 



3. Meal and floats 0.1561 " " " 



4. Blood and floats 0.(J969 " 



5. Ammonite and floats 0.1052 " " " 



The filtrates, reeking as they were with organic matter, pos- 

 sessed a more or less opacity, and I w^as led to suspect that in 

 the cases of 2, 3, 4 and 5 there might be some of the finer por- 

 tions of the floats passed the filter. So I evaporated these four 

 filtrates down, which cau.sed a separation and collection of the 

 suspended matter, and filtered each into two parts, determining 

 the phosphoric acid in each of the filtrates and residues thus 

 obtained. The figures given in Table II are the sum of these 

 two determinations in each case. In every case but 3 (that of 

 the cotton seed meal) the phosphoric acid in the residue was in 

 excess of that in the filtrate, tending to show that most of the 

 phos})horic acid leached out from the rotted samples was 

 mechanically carried through the filter rather than pas.sed in 

 genuine solution. The cotton seed meal seems to have had most 

 effect. But, granting that the whole of it was carried through 

 in genuine solution, the per cent, is so sn)all as to show that 

 little reliance can be placed on the decomposition of the organic 

 matter with which our in.soluble phosphates are in contact as to 

 rendering these pho>])hates soluble. 



