93 BULLETIN No. 145 [April, 



Van Bemmelen (23) believed that the iron, calcium, silica, 

 phosphoric acid, etc., found in- the ash of the matiere noire by Eg- 

 gertz, were not originally chemically combined to carbon in the 

 organic matter of the soil but were absorbed by the precipitated 

 gelatinous matiere noire. According to Van Bemmelen the phos- 

 phorus existed in the soil principally as calcium phosphate with a 

 very small quantity occurring in the absorbed state in the form of 

 a colloidal en Humate-Silicat-Komple.i". 



Two questions seemed to be of paramount importance to Wik- 

 lund (25) regarding the work of Eggertz: first, was the amount 

 of the ammonia-soluble phosphorus obtained from different soils 

 constant? Second, did the phosphorus exist in the mullkorpers 

 (matiere noire of Grandeau) in chemical combination with carbon, 

 or simply as absorbed phosphorus? He concluded that there was 

 a tendency for the ammonia-soluble phosphorus to be constant in 

 different soils. He showed, further, that one digestion with 12 

 percent hydrochloric acid did not completely remove all of the 

 acid soluble phosphorus, but a second and even a third digestion 

 still removed some phosphorus. Now, he reasoned, if the phos- 

 phorus removed by the second and third digestion was simply ex- 

 tracted from the absorbed phosphorus, extraction of the soil with 

 ammonia after the first digestion with hydrochloric acid, should 

 yield a solution of matiere noire containing a higher phosphorus 

 content than when the soil was completely extracted with the hy- 

 drochloric acid. Such, however, was not the case, therefore, the 

 phosphorus did not exist as absorbed phosphorus and must be in 

 combination with carbon in the organic matter. 



Snyder (34) noted that some phosphorus, iron, etc., were ex- 

 tracted with the matiere noire but he did not seem to think at this 

 time that there was any evidence of combination with carbon. 

 About the same time he observed the rapid loss of phosphorus as- 

 sociated with the humus in continuous cultivated soil. 



According to Berthelot and Andre (27) phosphorus may be 

 found in the soil (a) in inorganic or mineral phosphates, (b) in 

 organic ethers and (c) in organic or mineral compounds not read- 

 ily decomposed. 



Schmoeger (29) reviewed the rival claims of Eggertz and Nil- 

 son, and Wiklund on the one hand, and Van Bemmelen on the 

 other, regarding the phenomenon of ignition rendering the phos- 

 phorus of peaty soil more readily soluble in acids. 



It seemed possible to Schmoeger that the soil might possess 

 such a tenacious absorbent power for phosphorus that it would not 

 yield up its phosphorus to acid treatment before ignition. But he 

 deduced experimental evidence to show that such was not the case. 



