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



' ■ Mm 



fluence of friction and of increased temperature upon the direction of the 

 currents were the same. The molecular movements, therefore, produced 

 by friction are not in all cases similar to those produced by heat. 



Influence of Magne-optic rotating -power of the Liquids. 



Being desirous of determining whether the thermo-electric properties of 

 liquids were dependent on the molecular structure by virtue of which liquids 

 under the influence of magnetism polarize light circularly, I made the fol- 

 lowing apparatus and experiment : — 



A and B (fig. 11) are two straight glass tubes, about f inch in diameter 

 and 10 inches long, with two similar (but bent) 

 tubes, C and D, attached to their free ends by 

 india-rubber tubing. The sloping ends of the 

 straight tubes are ground flat, and are joined 

 together securely at their edges by melted shel- 

 lac, with a thin and projecting sheet of platinum 

 between them to separate the liquids. E and 

 F are two strong electro-helices wound upon 

 stout tubes of soft iron which enclose the glass tubes. The apparatus 

 is secured upon a board in an inclined position with the sloping ends 

 of the tubes uppermost ; and the two helices are held together at their 

 upper ends by an india-rubber band, G. I filled one of the tubes with a 

 clear and strong solution of perchloride of iron (of negative magne-optic 

 rotatory power, see Verdet, Phil. Mag., June 1858), and the other with a 

 similar solution of chloride of nickel (of positive magne-optic rotatory 

 power), and connected the liquids in the bent tubes with a galvanometer 

 16 feet distant by means of the platinum wires H and I. I now excited 

 the helices in various ways by means of 12 strong Grove's cells ; no cur- 

 rent was induced in the liquid. I next heated the junction of the tubes 

 gradually ; the solution of iron became thermo-electro-positive, and a steady 

 but feeble deflection of the needles took place ; and during the continuance 

 of this current I again excited the helices in various ways as before ; again 

 no electrical effects were produced. The results of this experiment strongly 

 support the conclusion that the thermo-electric properties of liquids are 

 not dependent upon the magne-optic polarizing power of the liquids, nor 

 upon the properties of their mass. 



On examining the thermo-electric properties of the solution of ferric 

 chloride with platinum plates in the apparatus described in the * Philoso- 

 phical Magazine,' 1857, vol. xiii. p. 1, the hot platinum was strongly 

 negative, value of temporary deflection '8475. With the nickel solution, 

 similarly examined, the hot plate was also negative, value of deflection 

 •0409. These results agree with that obtained with the two tubes in the 

 last experiment, the more positive condition of the iron solution than 

 that of the nickel one determining the direction of the current in that 

 experiment. 



