AND STRAIN ON THE ACTION OF PHYSICAL FORCES. 
115 
Experiment XLI. 
An annealed iron wire, ’0065 square centim. in section, stretched by hand. 
Percentage of average 
Percentage of average temporary 
permanent decrease 
superior increase of resistance 
of resistance for 1° C. 
Percentage 
of stretched wire over unstretched 
between 20° 0. and 
increase of length. 
for 1°C. between 20° C. and 100° C. 
100° C. of 
+ signifies superior increase of 
stretched wire, 
stretched wire on rise of temperature. 
— signifies permanent 
increase. 
6-0 
+ •0071 
-•00165 
12-0 
+ •0055 
+ -00230 
Experiment XLII. 
An annealed copper wire, '095 centim. in diameter, hammered. 
Percentage 
increase of length. 
Percentage of average temporary 
superior increase of resistance 
of hammered wire over unhammered 
for 1° C. between 20° C. and 100° C. 
+ signifies superior increase of 
hammered wire on rise of temperature. 
Percentage of average 
permanent decrease 
of resistance of 
hammered wire for 
1° C. between 20° C. and 
100° C. 
1-74 
-•00340 
•00836 
5-81 
+ •00117 
•00603 
11-05 
+ -00122 
•00447 
21-36 
+ •00139 
•00072 
Experiment XLIII. 
An annealed iron wire, '063 centim. in diameter, hammered. 
Percentage increase 
of length. 
Percentage of average temporary 
superior increase of resistance of 
hammered wire over unhammered 
for 1° C. between 20° and 100° C. 
Percentage of average 
permanent decrease 
of resistance of 
hammered wire for 
+ signifies superior increase of 
1° C. between 
hammered wire on rise of 
20° and 100° C. 
temperature. 
6-13 
+ •0009 
•0033 
1072 
+ ■0000 
•0056 
Experiment XL1V. 
An annealed copper wire, '095 centim. in diameter, permanently twisted. 
Torsion in terms of a 
unit taken as the 
torsion in a wire 
1 centim. long 
w r hen twisted through 
one revolution. 
Percentage of average temporary 
superior increase of resistance 
of twisted wire over untwisted 
for 1° C. between 20° and 100° C. 
+ signifies superior increase of 
twisted wire on rise of 
temperature. 
Percentage of average 
permanent decrease 
of resistance 
of twisted wire for 
1° C. between 
20° and 100° C. 
0-652 
-•000797 
1-087 
-•000824 
•00003 
3-261 
-•000977 
•00015 
6-520 
+ •002097 
-•003074 
Q 2 
