340 



Mr. G. Gore on the Thermo-electric [Feb. 23, 



copper dishes into contact with liquids of unequal strength instead of un- 

 equal temperature. 



The tube C (fig. 1 ) was filled with the stronger mixture and closed at its 

 end in the dish A by an india-rubber bung, and the dish B filled to the line F 

 with the same mixture ; the dish A was then filled with the weaker mix- 

 ture up to the same level and the bung slowly withdrawn. The two cop- 

 per dishes, previously connected with the galvanometer, were next simul- 

 taneously immersed in the mixtures and the effect noted. The following 

 are the results obtained by this method : — 



Nitric Acid. 



Experiment I. — In A, 1 volume of acid diluted to 80 volumes. In B, 

 1 volume diluted to 40. Copper in A was positive temporarily, value 

 •02/0; and permanently, value *01 98. 



Experiment 2. — In A, 1 volume of acid diluted to 40 volumes. In B, 

 1 volume of acid diluted to 20 volumes. The copper plate in A was first 

 positive temporarily, value of deflection '0064 ; and then that in B per- 

 manently, value *2850. 



Experiment 3. — In A, 1 volume of acid diluted to 40 volumes. In B, 

 1 volume diluted to 10 volumes. Copper plate in B was positive tempo- 

 rarily, value '4863 ; and permanently, value '0819. 



Hydrochloric Acid. 



Experiment 1. — In A, 1 volume of acid diluted to 40 volumes. In B, 

 1 volume diluted to 20 volumes. The copper in B was positive temporarily, 

 value *9608 ; and permanently, value *1087. 



Experiment 2. — In A, 1 volume of acid diluted to 40 volumes. In B, 

 1 volume diluted to 26'66 volumes. The copper in B was positive tempo- 

 rarily, value '3479 ; and permanently, value '0702. 



Chloric Acid. 



In A, 1 volume of acid diluted to 80 volumes. In B, 1 volume diluted 

 to 40 volumes. The copper in B was positive temporarily, value *0036 ; 

 and permanently, value *0009. 



Sulphuric Acid. 



In A, 1 volume of acid diluted to 80 volumes. In B, 1 volume diluted 

 to 40 volumes. The copper in B was positive temporarily, value *0467; 

 and permanently, value *0330. 



On examining these results, it will be perceived, 1st, that only in one 

 half the number of the experiments did increased strength of liquid pro- 

 duce electrical currents similar in direction to those produced by increased 

 temperature ; and therefore the heat does not act simply by causing a 

 greater number of molecules of each individual substance to touch the hot 

 plate ; and, 2nd, that only in one of the experiments was the copper in the 

 weaker liquid both temporarily and permanently positive to that in the 



