Forces of some Metallic Alloys in Contact with Copper. 33 



conspicuous the influence of the molecular changes. In the de- 

 nomination of the combinations we shall always place first the 

 name of that substance to which the positive galvanic current at 

 the place of contact must go in order to produce a cooling. The 

 electromotive force of the combination generates therefore a cur- 

 rent which at the contact-place goes from the last-named to the 

 first-named body. The same direction always resulted also for 

 the thermoelectric current at the hotter place of contact. We 

 may therefore regard the first-named body as the electropositive, 

 and the last-named as the electronegative constituent of the com- 

 bination. 



Iron-copper. 



For the purpose of being able to compare the electromotive 

 force of the alloys with that of the unmixed metals, the combi- 

 nations iron-copper and copper-bismuth (in fact, the wires of 

 these combinations already used by M. Edlund) were first tried. 

 The determination of the electromotive force of the combination 

 iron-copper gave the following result : — 



Experiment 1. Current-intensity 



Deflections. 

 33-65 

 33-72 

 33-22 

 32-49 



= tan29°6'-5. 



Mean 



33-27 



Experiment 2. 

 s=tanl9°30'-5. 

 Deflections. 

 23-57 

 23-50 

 23-50 

 23-70 



Mean . 23*57 



The mean value of /3=2 # 911. 

 following values : — 



From Exp. 1, 

 Mean . . 



Experiment 3. 



s= tan 8° 35'. 



Deflections. 



11-37 



12-22 



12-20 



Mean . 11-9 

 With this we obtain for a the 



a = 82-42 



a = 77-74 

 * = 81-62 



a = 80-59 



At the end of the entire investigation the iron-copper combi- 

 nation was tested afresh to ascertain what changes might have 

 Phil. Mag. S. 4. Vol 47. No. 309. Jan. 1874. D 



