6 
DK. A. MATTHIESSEN AND M. VON BOSE ON THE INELUENCE OE 
To save space, the mean only of the eight observations will be given, as otherwise the 
number of tigm’es would be very great. Table I. may be taken as a fair example of the 
results obtained. The formulee from which the conducting powers have been calculated is 
where A is the conducting power at C., x the conducting power at 0°, and y and z 
constants. The values for x, y, and z were deduced from the mean of the observations 
by the method of least squares. 
We will now proceed to the experiments made with each metal, making at the same 
time a few remarks on their purification, &c., and then see what general laws and con- 
clusions we may draw from the results obtained. 
Silver. 
Purified by precipitating nitrate of silver with hydrochloric acid, and reducing the 
washed chloride with pure carbonate of sodium. Wires 1, 2, and 3 were of different 
preparations. Table II. gives the results obtained with these wires. 
Table II. 
First wire. 
Second wire. 
Tlrird wire. 
Hard drawn. 
Annealed. 
Hard di-awn. Annealed. 
Hard drawn. 
Annealed. 
Length 
1546 raillims. 
0'462 millini. 
1535 inillims. 
0-462 millim. 
1753 inillims. 1741 millims. 
0-596 millim. |0-596 millim. 
1962 millims. 
0*448 millim. 
1953 millims. 
0-648 millim. 
Diameter 
Conducting power 
found before heat- 
ingthe hard-drawn 
wires 
^ Eeduced to 0^. 
97*645 at 15*4 103-528 
98-138 at 16-2 104-364 
98-913 at 15-6 104-951 
99*837 at 16-0 106-091 
99*212 at 18-4 106*377 
99*586 at 17*4 106-380 
Q Reduced to 0°. 
95 - 112 at 16-0 101*149 
96- 618 at 15-6 102-585 
101*544 at 16-8 108-303* 
102-237 at 16-0 108-714 
101-427 at 19-2 109-162 
101-750 at 18-6 109-262 
^ Reduced to 0°. 
94- 053 at I 6 -O 99*800 
95- 241 at 15-4 100-839 
96 - 337 at 16-0 102-223 
96-671 at 17*6 103*178 
97*917 at 15-6 103-747 
97*669 at 17*4 104-168 
97*322 at 18-2 104-100 
Conducting power 
after being kept at 
100° for 1 day ... 
Ditto, for 2 days ... 
Ditto, for 3 days... 
jDitto, for 4 days ... 
|Ditto, for 5 days... 
Ditto, for 6 days ... 
The means of the conducting powers found for each of the following temperatures 
were — 
* During the day the temperature of the oil increased, by mistake, to 130°. 
