ae Sees ee ee St 
CS. ee a Te ot ee 
AS POLS er SPOS A eee 
PRRERS SES THRs roe, eee Tae oe 
and Resistance of a Galvanic Circuit. 51 
sistance of the copper is actually decreasing with the length of 
the measured wire, and this seems to indicate that at low inten- 
sities, the influence of temperature upon the resistance of con- 
duetors prevails over any other reason which, in a galvanic bat- 
tery, and with this method of determination and calculation, may 
modify the La pany. actually or apparently. 
It was desirable to determine the resistance of the copper wire 
at low intensities, me any interference on the part of high 
intensities. The last observation of each of the tables XII to XIV, 
each with 100 em. of platinum but with no copper wire in the 
circuit, enabled me to do so. From 
| there follows 
E E at toe E 
es ~~ W4O-LP, 3 W+P,’ 
PI(l,-T,)— Pala(t,=T)+P 1091s) 
I,(1,—I,) 
Putting T=0° 1900, Pi=30; I5=0: ‘0882, Ps=100, and afterwards 
=: 580, 44 =40; « = = all from table 
xu, and combining them Lora P a 6 with each of the observa- 
tions with from 50 to 100 em. of platinum, and 100 cm. of cop- 
per wire in the circuit, as per table x11; and further calculating, 
after the same manner, with the corresponding figures of tables 
Xin and xiv, there result, as the mean values from 12 single 
ones, the following resistances 
ngt Resistance of 
copper vite. Resistance. 25 cm. length. 
1 4465 1116 
150 5128 0°855 
200 5°125 0°641 
It becomes here more evident that at low intensities the spe- 
cific resistance of the copper wire appears to increase with the 
Benety, respectively with the temperature produced by it. 
urse the above figures cannot be compared with those 
given on page 50, since the latter values were derived from the 
highest direct intensity. In order to connect the results of both 
calculations, Icombined first, the intensities 0°8865 and 0-0882, 
and afterwards the intensities 0°378 and 0: 0832, with each of the 
six observations before the last, all of table xu. The values re- 
sulting therefrom, in columns 1 ‘and 2 of the following table, com- 
4. 
2 3. 
12°3 714 4°84 3°53 
9°74 6°62 4°73 9 
T13 5-02 3°66 3°25 
6°35 5°81 5°27 9 
5°08 4°73 4°53 4°49 
4°49 4°78 4°93 95 
, 4°66 4'2 
pared with those in eka 3 and 4, which the above mean 
value (4465) is derived from, go again to show a | de- 
