318 Intelligence and Miscellaneous Articles. 



and the quantity of heat regenerated under these circumstances wil* 

 be 



A 2 r 



C- 



M 



Now, working with 1, 2 ... 6, ... n plates, we have found that the 

 machine verified this formula, taking for A 2 and r the values 813*12 

 and 100. 



The following- are some of the results : — 



Resist- 





Thermal units reproduced in 



the circuit. 















ance X. 



Two plates. 



Three plates. 



Four plates. 



Five plates. 



Six plates. 



Obs. 



Calc. 



Obs. 



Calc. 



Obs. 



Calc. 



Obs. 



Calc. 



Obs. 



Calc. 



7-52 



127 



1-56 



2-72 



314 



4-75 



4-98 



6-20 



701 



8-35 



8-36 



1504 



2-30 



2-48 



4-55 



4-58 



6-{}5 



6-77 



9-05 



8-91 



10 85 



1100 



22-56 



2-86 



305 



518 



5-24 



745 



7-32 



9-57 



9-24 



10-71 



10-99 



30-08 



326 



3-37 



5-62 



5-50 



7-35 



7-37 



930 



902 



1051 



10-45 



46-40 



3-69 



3-67 



5-66 



547 



7-00 



6-91 



8-20 



8-02 



905 



9-01 



69-60 



3-81 



3-65 



5-33 



5 02 



5-90 



600 



Cv76 



6-74 



7-40 



7-32 



9208 



3-70 



341 



4-49 



4-50 



509 



5-21 



560 



5-81 



5-60 



613 



The laws we have established are not to be considered special to 

 the instrument which we have used ; we consider that they apply to 

 all electromotors of the same kind, and express the general laws of in- 

 duction. 



For the future it will be possible to calculate the work of these 

 machines just like that of batteries, by which their use may be better 

 regulated ; it will be necessary for this purpose to determine the 

 constants A and r. We have obtained an insight into the nature 

 of these constants, on which we will make a remark. 



In the case of a constant battery, the internal resistance is that of 

 the liquid in the troughs. This is not the case with our machine : r 

 is merely a coefficient which satisfies the formula, it is equal to 110 

 turns of the rheostat; and this resistance is only equal to 16. 



Hence, for the very short and inverted currents which are developed 

 in the plates when the induced currents pass, the bobbins have a very 

 great resistance, much greater than that found with prolonged cur- 

 rents—than that, in short, which enters into Ohm's formula. 



This circumstance alone characterizes induction, since it is the only 

 change which is introduced into the formula ; but it alone is sufficient 

 to explain the observed effects. If, in fact, the mngneto-electrical 

 machine had no other resistance than that of its wires, six plates 

 together would represent more than six metres of normal copper 

 wire ; it would act like a thermo-electric pile, and, having no resist- 

 ance, would produce effects neither of light nor tension. 



Tension, on the other hand, is the essential feature of induction ; 

 it can only be produced by an electromotor of great resistance ; and 

 by finding that this great resistance exists in the bobbins at the mo- 



