542 



Mr. G. Gore on 



this would be a parallel fact in the science of heat to that of the pro- 

 duction of electricity by contact action in electrical science. 



This research throws some light upon the origin of the voltaic cur- 

 rent, and the results accord with the original contact theory of Yolta (of 

 late years revived in this country), that electric currents may be pro- 

 duced between metals and liquids, by mutual contact, without the aid of 

 chemical action. 



I should much like to determine, by actual experiment, various 

 points suggested by this research : — 1st. Whether, by the mere contact 

 of a metal and liquid, an .alteration of temperature is produced. 2nd. 

 To make a model thermo- electromotor, composed of iron and a solution 

 of sodic carbonate ; and ascertain its electromotive power, and whether 

 a series of several such cells will electrolyse a liquid. 3rd. To test 

 the effect of rough and smooth surfaces of the plates. 4th. To en- 

 deavour to obtain an electric current with iron plates under the in- 

 fluence of magnetism. 5th. To search for other instances of molecular 

 change, also for other physical changes (such as that of irregular 

 absorption of heat) coincident with the molecular ones. 6th. To com- 

 pare the electromotive power of a platinum pair against one of iron, 

 gold, silver, &c., and to settle other questions which have occurred to 

 my mind. 



(Added March 17, 1878.) 



The thermo-electric properties of liquids appear to be related to the 

 statical electric effects of the contact of metals with liquids. Peclet 

 found that platinum and gold exhibited, by contact with acidulated 

 water, electric signs contrary to those which would have been pro- 

 duced had those metals been oxidised or chemically corroded ; also, 

 that they gave opposite electric signs with solutions of potash, am- 

 monia, or hydrosulphate of potassium, to those, which they gave with 

 dilute nitric, hydrochloric, or sulphuric acid. (See " Annal de Ohim.," 

 1841, vol. ii, pp. 233-255; "Arch, de l'Elect.," 1841, vol. i, pp. 621- 

 650; andDe la Rive's "Treatise on Electricity," English edition, vol. ii, 

 p. 849:) Pfaff, also, found those metals exhibit opposite electric signs 

 by contact with solutions of caustic potash, soda, or ammonia, to those 

 obtained by contact with strong nitric, hydrochloric, or sulphuric 

 acids. (See Poggendorff's "Annalen," 1840, vol. Ii, pp. 110-124, 

 197-212; Wiedemann's " Galvanismus," 1872, vol. i, p. 32; and 

 Peschel's " Elements of Physics," vol. hi, pp. 73-75.) Buff obtained 

 similar results to the above, with platinum in contact with solution of 

 potash, dilute nitric or sulphuric acid, commercial nitric acid, and in 

 fully concentrated nitric acid. (See Liebig's "Ann. de Chem. and 

 Pharm." 1842, vol. xlii, pp. 5-14; "Archives de l'Elect.," 1843, 

 vol. iii, pp. 561-572 ; Wiedemann's "Galvanismus," 1872, vol. i, p. 29.) 

 Each of these investigators also found platinum become charged with 



