404 RETD AGKICULTURE ALLIED TO CHEMISTRY. 



been elevated, and then the sands and gravels and claya of the 

 terraces heaped above his remains, — that he was a fossil, unchanged 

 and undisturbed, centuries perhaps before the Mastodons and Mam- 

 moths, whose bones v/ere found in the peat deposits of N. America, 

 including the tooth and thigh bone found in Cape Breton, which 

 has been referred by Geologists to the later genus, had begun their 

 existence. 



Art. XI. — Agriculture allied to Chemistry. By A. P. 

 Eeid, M. D., L. R. C. S., Edin., &c. 



{Read before the Institute Dec. 9, 1873.) 



In taking up this subject, I do not expect to give anything new, 

 or broach any form of theory, but rather to give a resume of the 

 previous and present ideas that to a great extent rule with those 

 who have paid most attention to the scientific cultivation of the soil. 



Previous to the present century these sciences were held to have 

 but few links in common, the authorities in either, with few excep- 

 tions, did not trespass their imaginary boundary line. Even Sir 

 Humphrey Davy in his lectures on the " Elements of Aojricultural , 

 Chemistry," (1802-18 12), did but shew that there was a relation 

 between the science of Chemistry and the art of Agriculture. 



Strange to say Boussingault, in 1836, after long study, experi- 

 ence and observation, came to the conclusion that the value of 

 manure was to a great extent indicated by the amount of nitrogen 

 and ammonia it contained — a theory that was rudely shaken to the 

 winds by the accomplished Liebig ; but it has again asserted itself, 

 and is not likely to be displaced, for experience has proved the 

 security of its foundation, and the accuracy of the study and obser- 

 vations of its founder. 



In 1840 Liebig propounded a most comprehensive, clear and 

 definite theory of plant nutrition that took the agricultural world 

 by storm and ruled for years, but it vanished, and was even given 

 up by its illustrious founder, long ere his late decease. I will very 

 briefly run over its landmarks, for it had much to do Avith the 

 extended and accurate observations of the past thirty years. 



