418 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



alumina is thus almost completely extracted, and is then pre- 

 cipitated (by expelling the sulphurous acid by heat) as a fine, 

 white, bulky powder, containing traces of iron and manga- 

 nese, a considerable amount of gypsum, and 30 to 40 per cent, 

 of combined phosphoric acid. The acid supernatant liquid is 

 next neutralized with lime or marl, when gypsum, also a fer- 

 tilizer, is thrown down with a portion of the previously un- 

 precipitated phosphate. If the large amount of mechanically 

 combined water can be got rid of, this new source of phos- 

 phoric acid is worthy the attention of agriculturists, since 

 about 2500 tons of the crude material are annually produced. 

 Liebig was especially interested in it, and suggested the im- 

 portance of combining the phosphoric acid with a base also 

 assimilable by plants perhaps with potash, by aid of a sili- 

 cate of potash. Conversion, by fluxing into a superphosphate, 

 as suggested by Jacoby, did not prove practical, on account 

 of the hygroscopic character of the product ; but by saturat- 

 ing sawdust with it, a superphosphate with 18 per cent, solu- 

 ble phosphate is obtained, which is too moist for transporta- 

 tion. Peat is suggested by Breitenlohner as a valuable sub- 

 stitute for sawdust. 28 (7, 3Iay, 1873, 268. 



TENTH ANNUAL REPORT OF THE MASSACHUSETTS AGRICULT- 

 URAL COLLEGE. 



The tenth annual report of the Massachusetts Agricultur- 

 al College, presented in January of the present year, has just 

 been published, and contains a considerable amount of mat- 

 ter of interest to agriculturists. Not the least important is 

 the report on Commercial Fertilizers by Professor Goessman, 

 in which he takes into consideration the subject of fertiliza- 

 tion generally, in reference to the commercial fertilizers usu- 

 ally employed, and gives a sketch of the kinds recently intro- 

 duced. He also presents the result of 'an analysis of a num- 

 ber of the fertilizers in use among the farmers of Massachu- 

 setts. In reference to stable manure, which is now the main 

 fertilizer in ordinary farming operations, he states that its 

 value depends more upon its influence upon the physical con- 

 dition of the soil than in adding important constituents ; and 

 by a tabular statement of the ingredients he shows that, al- 

 though the most complex of fertilizers, it can claim to possess 

 this function only exceptionally, and that the permanent ira- 



