92 MK. SOLLY ON THE 



ever, of Dr. Ingenhousz, so far from strengthening his position, 

 in truth prove nothing whatever : because, as is well known, the 

 interior of a charged Leyden jar contains no electricity what- 

 ever ; and therefore, in placing seeds in the inside of a jar, he 

 placed them in a situation of all others the worst for the influence 

 of electricity on them. Electricity always tends to occupy the 

 outer surface of substances, and consequently is found entirely 

 on the outside of any piece of metal, whether it be solid or hol- 

 low ; in the Leyden jars the electricity of the two coatings is 

 powerfully drawn together, and accordingly the charge wholly 

 exists on the surfaces of the tin-foil in contact with the glass, 

 the outside of the interior tin-foil, and the inside of the outer foil, 

 and this holds good whether the jar contain only air, ger- 

 minating seeds, or mercurj', &c. ; it is indifferent what matter is 

 placed inside the jar, the whole of the electricity is collected on 

 that side of the tin-foil which is in contact with the glass. For 

 this reason it is evident that Dr. Ingenhousz's experiment did 

 not establish the points which he endeavoured to prove : his 

 results were, however, confirmed by Sylvestre, who described a 

 number of experiments in the ' Memoires de la Societe d' Agri- 

 culture de Paris, pour 1791,' and by Pacts, Van Troostwyck, 

 and Krayenhoff, in their ' Application de I'Electricite a 1' Agri- 

 culture et a la Mt^decine.' These philosophers found no difference 

 occasioned in the germination and subsequent growth of seeds ; 

 or if any difference whatever was perceptible, it was in favour of 

 the seeds which were not electrified. The first experiment 

 which they made was in favour of the effect of electricity ; but, 

 on repeating and varying it, they came to the same conclusion 

 as that at which Ingenhousz had arrived. 



In 1788 Dr. Ingenhousz published some observations on the 

 influence of atmospheric electricity on the growth of plants,* in 

 which he further examines some of Bertholon's statements, and 

 particularly witli regard to some cases of rapid growth in the 

 neighbourhood of lightning conductors, which Bertholon had 

 attributed to the influence of electricity. The most important 

 case of this sort was one communicated to Bertholon by the Abbe 

 Toaldo.j M. Quirini, some years since, had had a lightning 

 conductor constructed at his beautiful country seat on the banks 

 of the Brenta. This apparatus, consisting of a high pole, sur- 

 mounted by a bar of iron which reached considerably above the 

 roof, was placed in an angle of the walls at the back of the house, 

 on the northern aspect ; by these walls M. Quirini had a row of 



* Rozier, 1788, i. p. 81. 



t Bertholon, de I'Electricite des Meteores, Lyons, 1787, vol. ii. p. 370. 



