An Account of a new Eudiometer. 175 



equally good order, and the weather equally favourable ; but whenever an increafe or di- 

 minution was obfervcd upon trying one wire, a fimilar change was perceived, upon chang- 

 ing it for the other. 



I have alfo found, that plants cannot be altogether faid to be non-condu£lors of Galva- 

 nifm ; by connefting one end of the pile with the ftena of a plant, and taking the other wire 

 in the hand. When the tongue was applied to any of the leaves, even at a confiderablc 

 diftance from the ftem, a flight tafte was perceived ; but though I allowed the fame plant 

 to remain for above twelve hours with the two ends of the pile connected with different 

 parts of it, it fuftained no injury whatever. It is to be obferved, that the pile was ftrong 

 enough to give a very fevere fhock through feveral human bodies. 



I think the refult of the above muft lead us to conclude, that though a fmall quantity of 

 eleftricity may attend the phenomena of Galvanifm, (and there is fcarcely an operation ia 

 nature wherein a fmall quantity is not produced, and as you yourfelf have obferved, that 

 the very motions of the human body, and the drapery that covers it, will produce fome:) 

 yet that the principal phenomena of Galvanifm, viz. the fhock, the fpark, and the 

 fnap, are not eledlrical, and we muft here ufe the fame mode of reafoning, that we 

 would in chemiftry, that when one of the leading properties of any body was abfent, that 

 it muft have loft it, either by combination with another, or by decompofition ; but as you 

 are inclined to attribute the want of the efFe£t of attrafling light bodies to the want of velo- 

 city in Galvanifm, I beg to be informed, whether Mr. Cruickfhank's very powerful machine 

 afFefts the eleftrometcr equally with an eledrical vial of the fame ftrength, for I am at a 

 lofs what to call velocity, if the ellifion of light from the air, producing a found to be 

 heard in another room, and rufhing to a condu£tor at a diftance, be not inftances of velo- 

 city equal to any obferved in eleftricity.. 



"With the greateft refpeft, and thanks both to you and Mr, Cruickfhanks, for the rea- 

 dinefs with which you attended to my laft, and the full explanation you took the trouble 

 to honour me with,^ 



I am, SIR, 

 A FRIEND TO THE EXPERIMENTAL RESEARCH OF TRUTH. 



V. 



An Account of a new Eudiometer. By Mr. DaVY. From the Journal of the Royal 



Injiitution, 



T. 



HE dependance of the health and exiftence of animals upon a peculiar ftate of the at- 

 mofphere, and the relations of this ftate to procefTes conneQed with the moft efTential 

 wants of life, have given intereft and importance to inquiries concerning the compofition 

 and properties of atmofpheric air. 



This 



