TEMPERATUEE ON THE ELECTEIC CONDUCTING POWEE OE METALS. 25 
a wire does not increase in direct ratio to the temperature (as stated by some experi- 
menters in this direction), but, on the contrary, the formula for correction of the resist- 
ance of a wire for temperature is 
and not 
r=x-\-yt-{-zf, 
rz=x-{-yt. 
Table XIX. 
First wire, hard drawn. 
First wire, annealed. 1 
Second wire, hard drawn. 
Second wire, annealed. 
T. 
Eesistance. 
Increase of 
resistance 
for 1°. 
T. 
Eesistance. 
Increase of 
resistance 
for 1°. i 
T. 
Eesistance. 
Increase of 
resistance 
for 1°. 
T. 
Eesistance. 
Increase of 
resistance 
for r. 
0 
0 
16-86 
29-88 
51-03 
69-52 
83-77 
98-60 
98-382 
104-74 
109-81 
118-72 
126-59 
132-60 
139-22 
0-3771 
0-3825 
0-3985 
0-4057 
0-4085 
0-4142 
O 
0 
17-0 
29-63 
50-22 
69-60 
83-42 
99-37 
98-241 
104-67 
109-54 
118-08 
126-23 
132-21 
139-10 
0-3782 
0-3813 
0-3950 
0-4021 
0-4072 
0-4112 
O 
0 
19-17 
30-95 
48-53 
69-22 
83-77 
99-00 
98-412 
105-98 
110-88 
118-32 
127-16 
133-31 
139-80 
0-3948 
0-4028 
0-4102 
0-4153 
0-4166 
0-4181 
O 
0 
18-96 
31-86 
52-05 
70-27 
83-81 
99-57 
97-902 
105-28 
110-59 
119-08 
126-85 
132-58 
139-36 
0-3891 
0-3982 
0-4069 
0-4119 
0-4138 
0-4164 
Third wire, hard drawn. 
1 
Tliird wire, annealed. ! 
Eesistance calculated from the 
mean of the six formulas 
found for copper. 
Eesistance calculated from the 
mean of all the formulae. 
0 
12-65 
25-61 
39-52 
53-92 
69-90 
84-87 
99-92 
99-384 
104-42 
109-82 
115-72 
121-85 
128-54 
134-82 
140-94 
0-3981 
0-4075 
0-4134 
0-4167 
0-4171 
0-4175 
0-4159 
O 
0 
' 13-45 
26-15 
1 39-35 
\ 55-50 
^ 69-90 
1 84-67 
99-05 
97-806 
103-14 
108-41 
113-99 
120-95 
127-00 
133-25 
139-32 
0-3966 
0-4055 
0-4113 
0-4170 
0-4176 
0-4186 
0-4190 
O 
0 
20 
40 
60 
80 
100 
100 
107-97 
116-33 
124-98 
133-69 
142-22 
0-3985 
0-4082 
0-4163 
0-4211 
0-4222 
O 
0 
20 
40 
60 
80 
100 
100 
107-76 
115-91 
124-36 
132-92 
141-46 
0-3880 
0-3977 
0-4060 
0-4115 
0-4146 
The calculations from a formula of four or more terms, as 
X =x-\-yt-\-zt^-\-af, 
agi’ee better with the observed values than that of three. An example of this is shown 
in Table XX., where the formulae, deduced from observations made with a hard-drawn 
wire (of course previously heated to 100° for several days), of three and four terms, with 
the differences, are given. 
MDCCCLXII 
E 
