280 Upon Caloric as a cause of Galvanic Currents. 
Positive current and caloric 
moving 
together jin sppenition. 
<_< | > Remarks. 
cold, hot. | hot. cold. 
+ -l+ = 
oT a & T 
‘and 
Zinc. BLE STo8eZ. £ N ff h hot ti Th bth bi 
y , é o effect wit a in, e er combin- 
Gol... 1 Th &G. § a wees facts 
Iron. . eicacpeh: he Be Hot tin no effe ri 
Mercury. . Pte em | No. 1. very feeble. | 
1.T.& N.| For No. 2. the nickel must be made red 
Nickel. . ‘+ |2N.&T.| hot. 
Zinc. eas bal BOGE: 
and : : 
Gold.. . .|Z.&G. |Z&G. | No.2.very feeble. 
ies ett. ideo abe Ze Hot zinc no effect. 
Mercury. ; : b Mee 
Nickel. . 
GoLp ‘ Ree tay a: ee 
ai ‘ 
Iron L&G L.& G. No. 2. much more powerful than the other. 
Mercury. ‘ ‘ “ = - he } These effects very indistinct. 
Nickel. . . | | 
AON a be eet hel 
and | | 
Mercury. .'1.&M. !1.&M 
Nickel. . .[1&N. |L&N. | 
MERcuRY. M.& M. | 
Nickel. . | 
Nroxsn.:. |... -{ NGN. J 
Although this communication relates to the metals in their elemen- 
tary state, there are several other substances, which, in consequence 
of their being good conductors, are capable of acting as powerful 
electromotors, both by heat and acids. Among these may be speci- 
fied most of the iron ores holding the protoxide, the sulphuret of 
iron, charcoal, plumbago, &c. I found a specimen of the load-stone, 
in my possession, to possess this power to a much greater extent than 
many of the metals. These natural productions are distinguished 
by being, as far as my observation extended, negative, as to the cur- 
rent, with all the metals, not even excepting bismuth. The energy 
with which they act upon the galvanometer, by the contact of fluid 
matter, at once explains the fallacy of those recent experiments with 
this instrument, the object of which was to prove that galvanic cur- 
