INFLUENCE OF ELECTRICITY ON VEGETATION. 101 



influence upon plants, to separate the effects of the one from 

 those produced by the t>ther, though the two are most intimately 

 connected together. 



That electricity of tension should produce some effect on 

 growing plants might certainly be expected from its known 

 povrers ; and that it does in nature exert considerable direct in- 

 fluence upon the growth of plants is more than probable, though 

 certainly not to the extent wliich some of the older electricians 

 imagined. There are three ways in which electricity may be 

 supposed to act upon plants — chemically, mechanically, and as a 

 stimulant. Atmospheric electricity, it is well known, occasions 

 the formation of nitric acid in the atmosphei'c, and this effect may 

 probably be produced by some of the more quiet forms of elec- 

 tric discharge, as well as in thunder-storms ; it may, and in fact no 

 doubt does, assist in the formation of certain matters essential to 

 the growth of plants, as well as to the decomposition of various 

 compounds in their structure. If we adopt the view which many 

 considerations have of late years strengthened and confirmed, 

 tliat chemical action is but a modification of electricity, we may 

 say, with strong plausibility, that the growth of plants, the de- 

 composition of carbonic acid, water, and ammonia, &c., is a mere 

 electrical effect ; but in this case the negative and positive elec- 

 tricity evolved by these molecular changes is not set free in an 

 independent or current form, but neutralise each other at the 

 moment of evolution. The moving power of these changes is 

 generally stated to be light, or " vital energy " under the influ- 

 ence of light ; but the true nature of the relation which exists 

 between chemical action, light, and electricity, is far from being 

 yet understood. 



The mechanical effects of atmospheric electricity on vegetation, 

 such as augmenting exosmose, endosmose, and evaporation, «fec., 

 can hardly be very important, though, being constantly in ope- 

 ration, they may in the end have considerable influence on plants. 



The stimulating effects of electricity, or rather the question whe- 

 ther electricity does possess any stimulating effects on plants, is a 

 serious and important subject of inquiry, and one well deserving in- 

 vestigation. There appears little evidence to prove that plants pos- 

 sess any nervous irritability analogous to that of animals — a fact for 

 which we might be prepared by the absence of any organs corre- 

 sponding to nerves ; yet there are many curious facts connected 

 with the irritability of certain parts of plants, the influence of 

 external agents on the circulation of the fluids of plants as evinced 

 by the movement of solid particles in the cells, which very closely 

 resemble electric effects, and can better be explained on electrical 

 grounds, tlian on any other. What connexion may exist between 



