ELECTRICITY AND PLANT-GROWING. 75 



usually better mechanical condition than that of the control plots. 

 Or even if the soil were to be removed and replaced in the controls, 

 the presence of the wires and plates would of itself introduce a 

 great element of error, for the wires would become important 

 factors in aerating and draining the soil and probably in modifying 

 its temperature ; and metal plates would certainly be likely to 

 iuHuence soil temperature. It is well known that in certain cases 

 the germination of seeds can be hastened by running a twig down 

 ■to them : it becomes a means of providing oxygen from the air, 

 and probably, also, of relieving the soil of some of its superfluous 

 water. One of the important advantages of plowing under coarse 

 manures or green crops is the mechanical etfect which follows, for 

 every strand of vegetable fiber forms a tube for the passage of 

 water and air. And it has long been the practice in cool 

 countries to put earthenware or other plates beneath fruit trees to 

 warm their feet. While I am convinced that the application of 

 electricity to the soil may produce marked effects upon vegeta- 

 tion, I shall not be ready to accept the results of experiments 

 until the control plots are wired like the others — with non- 

 conducting material, of course — and the temperatures and 

 humidity of the soil are given careful attention. 



3. It is very probable that atmospheric electricity exerts a 

 powerful influence upon vegetation. The experiments of 

 Grandeau, cited above, were designed to determine this point. 

 Plants were grown in the free atmosphere, which is always in a 

 greater or less state of electrification, and also in a wire cage from 

 which the atmospheric electricity was excluded. Maize in the free 

 air was in every way better than the other, not only in the bulk of 

 all its parts, but in the amount of ash, and of both nitrogenous and 

 non-nitrogenous matters. Leclerc, who made investigations at the 

 same time, arrived at identical results. Grandeau's conclusions 

 are as follows : 



1. Atmospheric electricity exerts a considerable influence upon 

 the production of vegetable matter. Other things being equal, 

 plants will develop better when exposed to the influence of 

 atmospheric electricity. 



2. Plants deprived of the influence of atmospheric electricity 

 have, in the same length of time, given 50 to 70 per cent less bulk 

 and 50 to 60 per cent less fruit and seeds than the plants subjected 

 to normal conditions; i. e., those to which atmospheric electricity 

 has free access. 



