eet iain) 
and Resistance of a Galvanic Circuit. 385 
given in tables 1, 111, Iv, and v. Since, according to the form- 
ula HE=RI,, both the electro-motive force and the internal re- 
sistance maintain the same relation, I calculated for these, and 
all the following tables, only the internal resistance. Table 111 
shows an increase from 2°98 to 5°52, not quite as much as table 
I; though the direct intensity is about the rene while the ex- 
ternal resistance has been increased very much. ‘Tables 11 and 
Iv plainly demonstrate, as a general rule, that the increase of the 
internal resistance becomes less remarkable when the direct in- 
tensity of the battery is low. This rule, however, has its pei 
tions, and table v exhibits a very remarkable case. The direc 
intensity of this battery is less than in table u, still nes one 
of the internal resistance is much greater than in this t 
These results vexed me the more, since I eudentonk the ex- 
periments mainly for practical purposes. e experiments de- 
layed my proposed investigation, and I could not anticipate any 
direct profit. I therefore : concluded to give up, for the pres- 
ent, determining the constants of the battery, as they were not 
p 
fol rom 
E E PASM, 
=p L= R50 =a opP. that v= (I, oR ih . 
As table v shows, the resistance of the copper wire “ caleu- 
lated in this manner, increases with the decrease of the observed 
intensities, just the same as the internal resistance did. - d no 
limit being fixed, there could not be placed any reliability in’ 
any one of these calculated resistances, nor could I, with such a 
method, determine at all any resistance, under circumstances 
similar to those I proposed to try within the electro-magnetic 
machine. I now was compelled to investigate the matter at 
once, 
As mentioned above, the reason for the increase of the inter- 
nal resistance may be the relations existing between the intensity 
of the current, the heat developed by it within the circuit, and 
the influence of te temperature upon the resistance of conductors. 
Jadeed, the heating of the platinum wire makes our unit of re- 
sistance greater than the resistance of a unit of length of the 
wire at common temperature. And the liquids in the cup being 
