6 
MK. J. KEGIXALI) ASinVOKTH; 
3. Ill order detinitely to test this conclusion, it was necessary to procure samples 
of wires drawn down liner and finer from one original piece, and IMessrs. W. Smith 
and Soxs, of Warrington, kindly undertook to supply them. The first delivery which 
came to hand was drawn successively from a wire about 0T59 centim. in diameter, 
the appearance of the wire being like this :— 
The material of the whole was one and the same, and the only difierence between 
one part and another was the amount of traction which had been applied. Lengths 
were cut off from every stage in the drawing, so that each piece was 100 times 
longer than its diameter, and all were separately magnetised between the poles of a 
powerful electromagnet and then immediately examined for magnetic properties. 
The coefficient wdiich, at the first, is incremental (marked in Table II. ufith the 
Table II.—Residual Magnetic Intensity and Temperature Coefficient for Successive 
Amounts of Traction. 
Fine Piano Wire. 
1 
i No. 
Diameter. 
Dimension 
ratio. 
Residual intensity 
initially. 
Temperature 
coefficient, a. 
la 
eentims. 
0-159 
100 
608 
X lO-L 
+ 2-66 
8ff 
0-134 
100 
677 
+ 2-39 
9rt 
0-118 
100 
690 
+ 2-54 
10« 
0-106 
100 
785 
+ 2-27 
11a 
0-091 
100 
866 
+ 2-32 
12a 
0-089 
100 
915 
+ 2-25 
13a 
0-067 
100 
970 
_ 
+ 1- 22 
positive sign^), becomes not more so, but less so as the drawing proceeds, and is finally 
only half as large as at the begiiining, and it seems as if extreme traction might 
ultimately reduce it to zero. This unexpected result indicates that, if drav ing 
produces the abnormal effect, there must Ije some stage earlier than the first of this 
series where a maximum incremental coefficient would l)e developed. It liecame 
necessary again to apply to Messrs. W. Smith and Sons to prepare for me a 
complete set of Mures drawn successively as before, but beginning noAv at the rough 
* Ill a previous paper on this subject (‘iioy. Soc. Proc.,’ vol. 62, p. 210) ;ui opposite coinentiou was 
employed in regard to the sign, following an older usage. 
