1823.] M. Schweigger's Electromagnetic Multiplier. 445 



entirely interrupted the thermoelectric current. In a state of 

 such perfect isolation, no sensible chemical effect could be 

 expected. From the slight intensity indicated by the multiplier, 

 there is reason to think that it would require an electric circuit 

 of many hundred elements to pervade a fluid equally well as a 

 Volta's pile formed of four or five elements ; but it is very pro- 

 bable that such an apparatus will produce effects similar to 

 those which may be expected from hydroelectric piles, the 

 metallic elements of which are enormously large. 



Exper. 10. — The action of electrical currents upon animal 

 bodies is one of the most remarkable which it exerts. The 

 thermoelectric circuit excited no sensible taste, when it was 

 made to act upon the tongue ; but upon a prepared frog, it pro- 

 duced effects of two slightly different metals ; this result evinced 

 that the nerves of a frog are excellent conductors. 



Exper. 11. — A. thermoelectric circuit of 13 elements produced 

 no effect upon the most delicate electrometers ; nor did Volta's 

 condenser unequivocally indicate signs of electricity in this 

 circuit. But we acknowledge that we did not repeat this expe- 

 riment so often as it deserves. 



Exper. 12. — The experiments which we have related are suffi- 

 cient to prove how weak the thermoelectric current is with rela- 

 tion to the conducting power even of the best conductors. 

 Another experiment produced similar results under other forms. 

 The great circuit consisting of a rectangle, the length of which 

 was nearly four times its width, was placed in such a manner that 

 the two short sides were parallel to the needle of the compass ; 

 the compass was placed on one of these sides, and the two adja- 

 cent elements were rendered active. After having observed the 

 deviation of the needle, a communication was effected between 

 the active parts furthest from the compass by means of a copper 

 wire, so that all the active parts might form a separate circuit. 

 After this diminution of the circumference of the circuit, the 

 needle indicated a stronger action ; this effect would not have 

 been very evident, if the transmission of the thermoelectric cur- 

 rent were not so difficult even in the metal, that a difference of 

 passage of two or three feet could produce so considerable a 

 change in the effect. It must be observed that the same 

 copper wire employed to effect the communication, when 

 some part of the whole circuit was interrupted, would pro- 

 duce scarcely the same effect as the immediate junction. When 

 the part of the circuit furthest from the compass was ren- 

 dered active, and a similar communication was effected, the 

 deviation of the needle diminished. However, this difficulty of 

 transmission is unattended with any thing that ought to occasion 

 surprise. For the electricity in a circuit of conductors, in con- 

 sequence of their contact, must flow in proportion as it acquires 

 the intensity requisite to clear the passage in these conductors ; 

 therefore this electricity never acquires sufficient intensity to 



