SECT, xxxiv.] THERMO-ELECTKTCITY. 375 



the phenomena of repulsion, attraction, and rotation may be 

 exhibited by a thermo-electric current. M. Botto, of Turin, 

 has decomposed water and some solutions by thermo- 

 electricity ; and very recently the Gav. Antinori of Florence 

 has succeeded in obtaining a brilliant spark with the aid of 

 an electro-dynamic coil. 



The principle of thermo-electricity has been employed by 

 MM. Nobili and Melloni for measuring extremely minute 

 quantities of heat in their experiments on the instantaneous 

 transmission of radiant caloric. The thermo-multiplier, 

 which they constructed for that purpose, consists of a series 

 of alternate bars, or rather fine wires of bismuth and anti- 

 mony, placed side by side, and the extremities alternately 

 soldered together. When heat is applied to one end of this 

 apparatus, the other remaining at its natural temperature, 

 currents of electricity flow through each pair of bars, 

 which are conveyed by wires to a delicate galvanometer, 

 the needle of which points out the intensity of the elec- 

 tricity conveyed, and consequently that of the heat em- 

 ployed. This instrument is so delicate that the comparative 

 warmth of different insects has been ascertained by means 

 of it. 



