84 MR. SOLLY ON THE 



and electrified the one box ; the plants grew far more rapidly 

 than those in the other box ; their relative size, after eight days, 

 being as eight to five. 



From this period, for more than twenty years, very few ex- 

 periments on this subject are recorded, and we find it only oc- 

 casionally referred to by writers on electricity : thus, for ex- 

 ample, in 1752, Mr. J. Freke, in his curious treatise on the Nature 

 and Properties of Fire, quotes experiments on the influence of 

 electricity on the leaves of the sensitive plant, the irritability of 

 which was then by many considered of electrical origin. He also 

 hazards a few remarks on the probable effect of electricity gene- 

 rally on the growth of plants, and on their reproduction in par- 

 ticular, evidently considering electricity as the great moving 

 power of animated beings, and identical with nervous influence. 

 Priestley, in his 'History of Electricity,' 1768, after describing 

 the experiments of Maimbray, Nollet, and Jallabert, supposes 

 that the expense of such investigations has prevented other elec- 

 tricians from repeating and extending them, and observes that 

 the subject is one of great interest, and well deserving further 

 examination. The only method by which this can be done, he 

 observes, is by the help of a machine for pei'petual electrification, 

 to go by wind or water ; he does not appear to have made any 

 experiments himself, but seems perfectly satisfied with the cor- 

 rectness of the experiments of the French and Swiss electricians. 

 Professor Sigaud de la Fond, of Montpellier, in speaking of the 

 effects of electricity on organised substances,* and after describing 

 the experiments of Nollet, mentions some of his own, which had 

 led him to the same conclusions ; he found the bulbs of hya- 

 cinths, when electrified, grew faster and formed more healthy 

 plants than if not electrified. The probability of electricity 

 having a close connexion with the growth of plants is also 

 suggested by Duhamel,t who points out the effects of stormy 

 weather on vegetation, and supposes that electricity may be di- 

 rectly concerned in those remarkable atmospheric changes which 

 are observed to aflfect plants in so marked a manner. These 

 views are still further carried out by G. Beccaria, Professor of 

 Natural Philosophy at Turin. | He observes that electric clouds 

 begin to appear in the spring when vegetation commences, and 

 from time to time moisten the young plants with electric rains : 

 this electricity of the clouds is found to increase as the season 

 progresses, till the middle of autumn ; to be most abundant in 

 those showers which are accompanied with lightning, after which 



* Traite de I'Electricite, 1771, p. 374. f Physique des Arbres, 1758, vol. ii. 

 X Ellettricismo Artificiale, 1772, p. 283, 4. 



