356 Water y Met ah ; &c. Conductors [Book D. 



Dr. Fowler remarks, that he has frequently pafied 

 this influence through a great length of thin brafs wire, 

 and through the bodies of five perfons communicating 

 with each other by dipping their fingers in bafons of 

 water placed between them ; yet it did not appear to 

 have loft any of its force in this long and diffufed paf- 

 lage j for the contractions excited in the frog's leg 

 were equally itrong, as when it had pafied only through 

 one perfon. Dr. Fowler made many experiment in 

 order to difcover what fubftances were conductors and 

 what non- conductors of this influence. He found that 

 all metals when pure were excellent conductors j that 

 they were not quite fo good when in the ore ; and as 

 far as he could afcertain, lead fo when in the ftate of 

 metallic falts. From trials which he made with fome 

 of the calces of metals he concludes, that in that ftate 

 their capacity as conductors is quite deftroyed. Stones 

 feemed to be poffeffed of no conducting power. The 

 different non-conductors of electricity were found to 

 be non-conductors of this influence. Living vege- 

 tables afforded it a ready pafTage, probably from the 

 fluids which they contain. Oils of all kinds were fo 

 far from conducting, that if the fingers of the perfon 

 holding either the probe or the zinc have perfpired 

 much, even this operates as a complete obftruction to 

 the pafTage of the influence ; the inftant the perfpired 

 matter, has been wiped away, and the fingers have been 

 dipped in water, it again paries and excites contrac- 

 tions. Dr. Fowler wiihed to afcertain whether it pafied 

 over the furface or through the fubftance of metals ; 

 he coated feveral rods of different metals with fealing- 

 wax, leaving nothing but their ends, by which they 

 were held, uncovered. Contractions were excited as 

 readily through the medium of thefe/as if they had 

 not been coated. It feems to meet with no obftruc- 

 tion 



