430 OHM ON THE GALVANIC CIRCUIT. 



({uently the extreme action of the same multipher may serve 

 not merely to determine the tensions in various circuits, but it 

 also indicates that the extreme action may be also augmented to 

 the same degree as the sum of the tensions is increased, which 

 may be effected by forming a voltaic combination "with several 

 simple circuits. If we represent the actual length of a coil of 

 the multiplier by /, its couductibility by x, and its section by 



CO, so that \ = , the expression for the extreme action of the 



multiplier is converted into 



A 



from which it will be seen that the extreme action of two mul- 

 Itpliers of different metals, constructed of wire of the same 

 thickness, are in the same ratio to each other as the conductibi- 

 lities of these metals, and that the extreme actions of tioo midti- 

 jjliers formed of wire of the same metal, are in the same pro- 

 portion to each other as the sections of the wires. All these 

 various peculiarities of the multiplier I have shown to be 

 founded on experience, partly on experiments performed by 

 other persons, and partly on those by myself*. The most 

 recent experiments made on this subject on thermo-circuits, 

 have, in a different, and, in a ceilain sense, opposite manner, 

 already afforded the conclusion deduced above from an equa- 

 tion of tlie reduced lengths, that the sum of the tensions in a 

 thermo-circuit is far weaker than in the ordinary hydro-circuits ; 

 and a preliminary comparison has convinced me, that, with re- 

 spect to the heating effects, if they are to be predicted with 

 certainty, a voltaic combination of some hundred well-chosen 

 simple thermo-circuits is requisite, and for chemical effects of 

 some energy a far greater apparatus. Experiments, which place 

 this prediction beyond doubt, will afford a new and not un- 

 important confirmation to the theoiy here propounded. 



The previous considerations are also sufficient to indicate the 

 process which is carried on when the galvanic chcuit is divided 

 at any place into two or more branches. For this purpose I 

 call attention to the cn-cumstance, that at the time we found 



A 



the equation .S = -y-, we also obtained the rule that the magni- 

 tude of the current in any homogeneous part of the galvanic, 



* bchvvciggei's /a/(rt!/c/(, 1826. Part 2; and 1827. 



