ANNALS 



OF 



PHILOSOPHY. 



NOVEMBER, 1823. 



Article I. 



Oil some Anomalous Appearances occurring in the Thermoelectric 

 Series, By the Rev. J. Gumming, MA. Professor of Chemis- 

 try in the University of Cambridge. 



(To the Editor of the Annals of Philosophy.) 

 MY DEAR SIU, Cambridge, Oct. 13, 1823. 



In forming the thermoelectric series, which you did me the 

 favour to insert in your journal, the metallic wires were con- 

 nected at one extremity, and then immersed in boiling mercury. 

 On varying this experiment, I find some anomalous appearances 

 which seem deserving of notice. 



If one of the wires be iron, and they be heated by a spirit 

 lamp, the deviation, in some cases, gradually attains a maximum, 

 then returns through zero, and at a red heat assumes an opposite 

 direction ; resembling in this respect the deviations made by 

 the alloy of antimony and bismuth mentioned in my first com- 

 munication to you on this subject. These effects, the detail of 

 which I have subjoined, took place when iron was connected 

 with silver, copper, gold, zinc, and brass, but not with platina 

 or lead, and I have not observed it in other cases where neither 

 of the wires was of iron. 



Deviations. 



Iron with silver 

 copper 



gold 

 brass, 

 zinc . 



New? Series, v o l . v i , 



10° 

 13 



7 

 17 



7 

 Positive 



8° at red heat 



ditto 

 ditto 

 ditto 



melting zinc 

 Negative 



