1823.] Prof, Ctimming on Thermoelectric Relations, S^c, 17^ 



The combination of platina and iron is very powerful, and has 

 the advantage of permitting the appUcation of great heat. That 

 of platina and silver is readily applied to exhibit the inverse 

 experiment, i. e. the motion of the thermoelectrics on the 

 approach of a magnet. A silver wire bent into the form A is 

 connected with a platina wire B into the form C E D F, either 

 by soldering or by fine platina wire ; the whole is suspended 

 from a point D. On heating one extremity E, and applyinsjthe 

 pole of a magnet to F, the apparatus revolves from left to right, 

 or vice versa, according as the pole of the magnet is N or S. 

 The apparatus I have used for the purpose weighs nine grains : 

 indeed I know no limit to its minuteness. 



The annexed figure represents an arrangement for producing 

 a perpetual rotation, by means of platina and silver wires poised 

 upon a magnet, and heated by a spirit-lamp. A B D C platina 

 wire ; Ab c defCf silver wire ; c N, support of the wires ; N S, 

 magnet; L, spirit-lamp. 



N? 



