188 
DES. A. MATTHIESSEN AND C. VOGT ON THE INFLUENCE OF 
Another example: the gold-copper alloy containing 0 - 71 volume per cent, gold (hard 
drawn) conducts 79-884 at 15 0, 3 ; the formula deduced in exactly the same manner as 
the above was 
*=83-843— 0-26810*+0-0005152F ; 
and the formula deduced from this, with the help of which the following calculated 
values were obtained, was 
*=84-204— 0-26926£ + 0-0005174f. 
T. 
Conducting-power. 
Difference. 
Observed. 
Calculated. 
17-27 
79-709 
79-708 
0-000 
28-98 
77-952 
78045 
-0093 
39-55 
74-154 
74-364 
-0-210 
54-26 
70-924 
71118 
-0-194 
69-26 
67-920 
68037 
-0-117 
83-86 
65-213 
65-263 
-0-050 
98-78 
62-645 
62-656 
-0011 
Again, let us take another example, the alloy Sn 4 Cd, for which the values (Table 
XIV.) obtained for r 100 o— /, 00 o and r 0 o— agree worse than any other in that Table; 
and if the results agree, it will show that the differences in these values are, as before 
stated, due to errors of observation. 
The first observed conducting-power was 14-259 at 6°-8. 
The formula deduced, as above, was 
*=14-641-0-055250£+0-0001158f. 
That deduced to calculate the conducting-powers for comparison with those observed, was 
*=14-455— 0-054673£+0-0001141f. 
T. 
Conducting-power. 
Difference. 
Observed. 
Calculated. 
8-72 
13-986 
13-968 
0-000 
25-52 
13-086 
13134 
-0-045 
39-50 
12-419 
1-2-473 
-0-054 
54-96 
11-770 
11-795 
-0-025 
69-40 
11-218 
10-211 
-1- 0-007 
84-02 
10-933 
10-666 
+0-067 
98-85 
10-333 
10-166 
+0-167 
These examples are sufficient to prove that the law we have put forth is correct for 
most of the two metal alloys ; we might have experimented with many more alloys whose 
conducting-power would have followed the above law, but we thought determinations 
with a few members of each group of alloys would suffice to prove its correctness for 
most of them. We have endeavoured rather to find the exemptions to the law than to 
obtain a large number of results which will agree with it. 
