42 



MK. SOLLY ON THE INFLUENCE OF 



VII. — Further Observations on the Influence of Electricity 

 on Vegetation. By Edward Solly, Esq., F.R.S., F.L.S., Hon. 

 Memb. Royal Agricultural Society, Professor of Chemistry 

 to the Horticultural Society, &c. 



(Communicated November, 1846.) 



In a preceding number of the Journal * I drew attention to the 

 subject of electricity in connection with the growth of plants, 

 and briefly recapitulated some of the more important of the 

 numerous investigations which have been made during the last 

 hundred years, with a view of determining the nature and extent 

 of the influence which electricity has been supposed to exert on 

 vegetation. I also described a few of the experiments on this 

 subject which were made last year in the gardens of the Hor- 

 ticultural Society at Chiswick ; the general tendency of which, 

 as far as the results of so comparatively small a series of experi- 

 ments may be trusted, was certainly opposed to the view that 

 electricity in its ordinary forms exerts any very marked in- 

 fluence on the growth of plants. The experiments described 

 were designed with the object of endeavouring to augment or 

 diminish the natural supply of electricity which, under ordinary 

 circumstances, might be supposed to affect the plants ; for it was 

 imagined that if this power played so important a part in the 

 phenomena of vegetation, any means which could either diminish 

 or increase the natural quantity of electricity in the earth on 

 plants would necessarily either assist or retard the growth of 

 such plants. No result of this kind, however, was produced ; 

 but this was of course only negative evidence, which might be 

 influenced by the form of the experiments and other circum- 

 stances ; and in drawing the general conclusion that the direct 

 effects of electricity on the growth of plants is far less than is 

 commonly supposed, I was led to do so by other experiments 

 than those described. Some of these I propose now to mention. 



In the experiments at Chiswick just alluded to, no direct 

 attempts were made to increase the natural effects of electricity 

 by augmenting its quantity from artificial sources, in the manner 

 described with such opposite results by the electricians of the 

 last century ; I was, however, enabled to make a series of ob- 

 servations of this nature through the kindness of Lord Hill, who 

 intrusted the management of the following experiments to his 

 excellent gardener Mr. F. Nieman, under whose superintendence 

 I was quite certain they would be carefully and accurately 

 carried out, and the results minutely observed and noted. 



The place selected for the experiments was one of the grape- 



* Vol. i. pp. 81—109. 



