904 Transactions of the American Institute. 



ferric phosphate. The author also found that the absorption power 

 of soils for phosphate, sulphate, and carbonate of potash, was much 

 greater than for nitrate of potash or chloride of potassium. The 

 corresponding salts of ammonia behaved in a similar manner. In 

 conclusion, he expressed the opinion that the absorptive action of 

 fioils was dependent upon true chemical aflBnities, in contradistinction 

 to the view that it is the eflfect of physical attractions. 



The president, Warren de la Rue, thought that caustic lime, so 

 largely used by the farmer, would have great influence in absorbing 

 phosphoric acid. 



Prof. Way said there would be more difficulty in determining the 

 degree of absorption of the carbonates of ammonia and potash 

 than of the other alkaline salts named. The existence of the hydrate 

 of alumina was a matter of doubt.. Clay is generally supposed to 

 occur in the form of a double silicate of alumina, and many kinds 

 contained lime, locked up in such a manner that it could not be 

 extracted by acids, yet they had the power of absorbing ammonia 

 without any apparent chemical change. 



Dr. Volcker said the results of his experiments in the main agreed 

 with those of Mr. Warrington. There was a kind of peroxide of 

 iron precipitated by lime which behaved in an extraordinary manner 

 as to the amount of phosphoric acid it could take up, and lime in 

 a soil has great influence in absorbing ammonia, so also has the 

 hydrated silica naturally occurring in soil, as well as other con- 

 gtituents, which had not been taken into account. 



There was a remarkable tendency in nature for " the soil to take 

 care of itself," and if there should happen to be a deficiency of any 

 one ingredient, this was quickly remedied by a proper selection 

 from the materials presented in the form of manure. 



Dr. Gilbert said the experiments described seemed to establish 

 certain points, but he doubted the applicability of these results to 

 soils as they really exist. Mr. Warrington replied that when lime 

 was present, with the oxyd of iron, these bases acted more power- 

 fully, but in the same direction. It was only a question of time as 

 to how much phosphoric acid would be absorbed in a ferruginous 

 soil. Humus seemed to be capable of absorbing free ammonia; it 

 was evident that each ingredient of the soil must be experimented, 

 upon separately. 



ADULTERATION OF DYES. 



A correspondent of the London Chemical News says that common 

 salt holds a prominent place among the substances used to adulterate 



