INFLUKNCE OF ELECTRICITY ON VEGETATION, 93 



wild jessamines planted, in order to shelter the house on that side 

 from the action of the moist northern winds. He found, after 

 a few years, that the two plants nearest to the lightning con- 

 ductor had increased with most extraordinary rapidity, having 

 reached to the roof of the house, a height of thirty feet, whilst 

 the other trees, which were cultivated with exactly the same care, 

 were not more than four feet high. This fact Bertholon con- 

 sidered as a most decisive proof of the truth of his views, and as 

 unquestionably the effect of the lightning conductor : a con- 

 clusion denied by Ingenhousz, who contrasts it with the state- 

 ment of Gardini respecting the monks' garden at Turin. The 

 importance of electrical rains he doubts, because plants grow well 

 in hot-houses where they never get any electrified water ; and 

 besides, he remarks, the greatest quantity of atmospheric elec- 

 tricity is not always apparent during the height of summer ; 

 snow, in fact, being often far more electric than rain. Ingen- 

 housz repeated Gardini's experiment with the wires across a 

 garden, in one case covering the plants with a complete network 

 of cross wires, but failed in observing any effect whatever on the 

 plants growing beneath. He also connected small pointed con- 

 ductors with a number of different trees in the garden, but 

 found no increase in their growth in consequence; in fact, the 

 most healthy tree of all seemed to be one to which no pointed 

 conductor happened to have been applied. These experiments 

 were also made at the same time by Herr van Breda, at Delft, in 

 Holland ; he found that horizontal wires suspended over plants 

 produced no effect on their vegetation, and a similar result 

 attended the case of pointed conductors attached to the tops of 

 trees.* 



These statements, coming from so careful and accurate a 

 philosopher as Dr. Ingenhousz, soon brought the theory of 

 electro-culture into complete discredit, and even some of its 

 warmest advocates began to change their opinions : it was not 

 long, however, before other naturalists took up the subject ; and 

 accordingly, in the two following years we find a number of 

 papers by different authors upon the effects of electricity on 

 vegetation. In November, 1788, M. Carmoy wrote a letter to 

 the Marquis de Vichi,! in which he describes a variety of ex- 

 periments, of which the following will serve as an example: — 

 He took three perfectly similar cylindrical vessels of tin-plate, 

 and filled them with fine sifted dry earth, upon the surface of 

 which he placed in each vessel three similar grains of wheat, 

 taken from the same ear ; he then surmounted each vessel with 



* Voigt's Magazin fur Physik, 6, iv. 76. f Rozier, 1788, ii. p 3.39. 



