EXPERIMENTAL RESEARCHES ON DRAWN STEEL. 
35 
an invariable structure maintained throughout the progress of the drawing. Indeed, 
it is not difficult to see from the fracture of the wires that as the drawing proceeds a 
fibrous structure is developed for several stages after tempering, and the formation 
of this fibrous structure may be of imj)ortance in augmenting the magnetic intensity. 
For the sake of comparison, Young’s modulus has been plotted on Diagram IX., 
the points being taken from a smooth curve of the modulus and traction, and the 
curs^e bears out the statement that an increase of density in general improves elastic 
properties. It also shows that elasticity and magnetic intensity are correlated. 
To complete this part of the investigation of the properties of drawn steel, it was 
intended to add an account of the changes which might take place in the cubical 
expansion of these wires, and to trace the connection of these with other changes, 
but although some preliminary experiments have been made, the results are not yet 
sufficiently advanced to be presented. 
This investigation has been carried out at the Owens College, Manchester, at 
intervals during the last tliree or four years, and I am greatly indebted to Professor 
Schuster for allowing me to avail myself of the facilities for research which tlie 
Physical Laboratory there provides. 
Table IX.—Influence of Drawing on liesistivity, Young’s Modulus, and their 
Temperature Coefficients, and Density. 
1 No. 
i 
Condition. 
Resi.stivity 
(at air tem¬ 
perature, 
about 16°). 
Ohms per 
centimetre 
cube, 
P- 
Temperature 
coefficient of 
resistivity, 
a. 
Young’s 
modulus (at 
air tempera¬ 
ture), 
Y. 
Temperature 
coefficient of 
Young’s 
modulus, 
/• 
Density. 
Grams, per 
cubic 
centimetre 
at 16°. 
X 10-^ 
X 10“3 
X 10" 
X 10-* 
1 
Rolled Rod 
1-601 
-8 3-43 
1-78 
- 3-35 
7-803. 
2 
Annealed 
1-796 
-8 2-94 
1-83 
- 1-64 
7-827 
3 
Hard drawn 
1-585 
-8 4-66 
1-85 
- 10-2 
7-815 
4 
Tempered 
1-784 
-83-49 
2-04 
- 2-30 
7-818 
5 
Cold drawn 
1-716 
-8 3-55 
2-04 
- 3-79 
7-813 
6 
1-657 
-8 3-48 
2-08 
- 5-90 
7-8.35 
7 
; > 
1-645 
-83-61 
2-11 
- 4-87 
7-871 
8 
1-638 
+ 3-51 
2-20 
- 2-79 
7-881 
! 9 
j? 
1-627 
+ 3-43 
2-13 
- 6-53 
7-902 
1 10 
3 ) 
1-633 
+ 3-52 
2-21 
- 1-79 
7-913 
11 
33 
1 - 696 
+ 3-44 
2-18 
- 6-42 
8-001 
12 
33 
1-738 
+ 3-48 
1-95 
- 4-24 
— 
12(1 
*3 
1-739 
_ 
_ 
13a 
33 
1-772 
— 
— 
_ 
_ 
14n 
53 
1-876 
— 
— 
— 
— 
Glass hard 
2-760 
+ 1-77 
— 
— 
7-740 
F 2 
FEiiSENTED 
17 MAR. 1903 
