280 Upon Caloric as a cause of Galvanic Currents. 



Positive current and caloric 

 moving 



togetlier 



H ^t 



cold. 

 + 



in opposition. 

 a WH- 



hot. 



+ 



cold. 



Remarks. 



Tin . 



and 



Zinc. . 



Gold. . 



Iron. . 



Mercury 



Nickel. 



Zijvc . 



and 

 Gold. . 

 Iron. . 



Mercury 



Nickel. 



Gold . 



and 



Iron. . 



Mercury 



Nickel. 



Iron , 



and 

 Mercury 

 Nickel. 



Mercitry 



and 

 Nickel. . 



NiCKEI.. 



T. &Z. 



T. &G. 



T. &.T. 



I &T. 



1. T.&M. 



2. M.&.T. 



1. T. &N. 



2. N. & T. 



Z. &G. 



I. &G. 



G. &G. 



I. &G. 



1. M. & G, 



2. G. & M. 



C No effect with hot tin. The other combin- 

 l ation very feeble. 

 Hot tin no effect. 



> No. 1. very feeble. 



For No. 2. the nickel must be made red 

 hot. 



No. 2. very feeble. 

 Hot zinc no effect. 



No. 2. much more powerful than the other. 

 > These effects very indistinct. 



. I N. & N. t 



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. Sec. 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- 



