Prof. Wheatstone on the TTiermo-electric Sparky S^c. 415 



confine myself to a simple statement and corroboration of the 

 facts, avoiding all theoretical considerations. 



The Cav. Antinori, Director of the Museum at Florence, 

 having heard that Prof. Linari, of the University of Siena, 

 had succeeded in obtaining the electric spark from the torpedo 

 by means of an electro-dynamic helix and a temporary magnet, 

 conceived that a spark might be obtained by applying the 

 same means to the thermo-electric pile. Appealing to experi- 

 ment his anticipations were fully realized. No account of the 

 original investigations of Antinori has yet reached this country, 

 but Prof. Linari, to whom he early communicated the results 

 he had obtained, immediately repeated them, and published 

 the following additional observations of his own in Llndica- 

 tore Sanese, No. 50, of Dec. 13, 1 836. ^ 



" 1. With an apparatus consisting of temporary magnets and 

 electro-dynamic spirals, the wire of which was 505 feet in 

 length, he obtained a brilliant spark from a thermo-electric 

 pile of Nobili's construction consisting only of 25 elements, 

 which was also observed in open daylight. 



" 2. With a wire 8 feet long coiled into a simple helix, the 

 spark constantly appeared in the dark, on breaking contact, 

 at every interruption of the current; with a wire 15 inches 

 long he saw it seldom, but distinctly ; and with a double pilej 

 even when the wire was only 8 inches long. In all the above- 

 mentioned cases the spark was observed only on breaking 

 contact, however much the length of the wire was dimi- 

 nished. 



" 3. The pile consisting merely of these few elements, and 

 within such restricted limits of temperature as those of ice 

 and boiling water, readily decomposed water. Short wires 

 were employed having oxidizable extremities ; the hydrogen 

 was sensibly evolved at one of the poles. 



" 4?. A mixture of marine salt moistened with water and of 

 nitrate of silver being placed between two small horizontal 

 plates of gold, communicating respectively with the wires of 

 the pile, the latter after having acted on the mixture gave evi- 

 dent signs of the appearance of revivified silver on the plate 

 which was next the antimony. 



"5. An unmagnetic needle placed within a close helix formed 

 by the wire of the circuit became well magnetized by the cur- 

 rent. 



" 6. Under the action of the same current the phaenomenon 

 of the palpitation of mercury was distinctly observed. " 



The interesting nature of these experiments induced me to 

 attempt to verify the principal result. The thermo-electric 

 pile I employed consisted of 33 elements of bismuth and an- 



