10 Biographical account of 



were plausible and formed important contributions to agri- 

 culture as a science was at once obvious. He conceived, that 

 lime was injurious in the form of quick-lime, and that it 

 proved beneficial by accelerating the decomposition and 

 promoting the solution of any hard vegetable matter in the 

 soil, contrary though it be to the views of many, who con- 

 sider that it acts as an instrument of saturation to the free 

 ulmic acid generated in the vegetable portion of the soil. 

 The beneficial action of gypsum on vegetables he attributes 

 to its entering into the composition of vegetables. This 

 opinion as stated exactly by Davy has not been corroborated 

 by Peschier* who found that the action of this salt upon 

 vegetables was in direct proportion to its state of solution, 

 and that its influence is null except when it is dissolved. 

 His experiments lead to the conclusion, that the sub- 

 stance is decomposed by electrical powers possessed by the 

 assimilating organs of the plant, and that the sulphuric 

 acid is set at liberty and combines with the potash in the 

 sap. 



Besides his study of agriculture, he became interested with 

 the investigations of meteorology, and in one of the num- 

 bers of the Institution Journal, he described his eudiometer 

 affording a simple method for ascertaining the proportion 

 of oxygen and azote in the atmosphere. It consisted merely 

 of a graduated glass tube and a solution of muriate or sul- 

 phate of iron at the minimum of oxidation, saturated with 

 nitrous gas. He published about this time, a paper on the 

 collision of steel and hard bodies, bearing on the question 

 of light, in the Institution Journal. In the Philosophical 

 Transactions for 1805, he published an analysis of Wavel- 

 lite, and another on the uses of boracicacid. But his most 

 important contribution to analytical chemistry, was con- 

 tained in his Bakerian lecture for 1806. " On some chemi- 

 cal agencies of electricity." At the conclusion of this 

 paper he makes some interesting observations on the nature 

 of electric chemical action in the mineral kingdom, which 

 have since been confirmed hy the researches of Becquerel. 

 He attributes the alteration in many of the rocky strata to 

 the influence of electrical agency. 



We come now to the year 1807 the most important in his 



* Records of General Science, iii. 477. 



