by the Immersion of unequally Heated Metals in Liquids. 3 



inches in diameter, but still obtained not the slightest current. 

 Each of the two vessels contained about 13 ounces by measure 

 of the solution. 



5. In each of these experiments the wires were very carefully 

 prepared, so that there was no interfering current produced by 

 difference of chemical action of the liquid upon them, or by dif- 

 ference of smoothness of their surfaces. The galvanometer was 

 an astatic one (or very nearly so), with very fine silk suspending 

 fibre (I have found a fine platinum suspending wire insufficiently 

 sensitive) ; its coil contained about 200 turns of moderately fine 

 copper wire (exact diameter 0*0075 inch), and ofi"ered no inju- 

 rious resistance ; the same instrument was used in all the suc- 

 ceeding experiments mentioned in this paper. 



6. From the foregoing results, I conclude that the currents 

 under consideration are not produced in any material degree by 

 any thermo-electric properties of the liquid alone, similar to those 

 which a single metal is known to possess. 



Description of Apparatus. 



7. To test whether chemical affinity takes any part in the pro- 

 duction of the currents, also to assist in settling various other 

 questions, I devised and constructed the following apparatus 

 (fig. 2). A is an open glass cylinder*, 2 inches long and 2 

 inches in internal diameter (with sides I of an inch thick), to 



Fig. 2. 

 Vertical section. Scale 1 inch to 2 inches. 



* I have since constantly used a vessel of an hour-glass form with p^reat 

 success. 



B2 



