PHILOSOPHICAL TRANSACTIONS 
I. E.xperimentdJ Researches on Draicn Steel. 
Bii J. IIeginald Ashworth, 31. Sc. {Vtct.). 
Communicated In/ Profr.'^sor A. Schuster, F.P.S. 
Ifcceived January 30,—Read March 6 , 1902. Received in revised form August 12, 1902. 
PART 1. 
The Influenx’e of Changes of Temperature on Magnetism. 
1. Introductory. 
2 . Influence of dimension ratio on residual magnetic intensity (I), temperature co¬ 
efficient (a), and permanent change (/3). 
3 . 4, 5. Influence of annealing, tempering, and drawing on a. 
6 . Influence of annealing, tempering, and drawing on I. 
7. Effect of rest in improving the drawing equalities of steel. 
8 . 9, 10. Curves of cyclic magnetisation of drawn steel, cold and hot, and their application 
to temperature coefficients. 
11. Relation of temperature coefficient to intensity when induced. 
12. Relation of temperature coefficient to intensity when residual. 
13. Repetition of § 12 with demagnetisation between each step. 
14. Similar experiments upon iron. 
15. Relation of susceptibility to a and /3 in drawn steel and in iron. 
16. Application of results to the construction of permanent magnets. 
17. Time tests of a and I on drawn steel magnets. 
18. Similar tests on tempered drawn steel magnets. 
Page 
C 
6 
9 
9 
10 
11 
13 
15 
16 
17 
19 
20 
22 
1 . The experiments which are included in this part are the outcome of a formei 
investigation, and relate chiefly to the influence of drawing on the magnetism of 
steel wires and its changes with moderate fluctuations of temperature. The effect of 
alterations of temperature on the residual magnetism of steel was examined many 
years ago by Wiedemann. His experiments, which have often been repeated, show 
that on heating a magnet to the temperature of steam much of the magnetism 
disappears, but that on cooling part of the magnetism so lost is restored; at each 
repetition of the heating and cooling the permanent loss becomes less and less, and 
ultimately the magnetic intensity fluctuates between two definite values, higher and 
lower intensities corresponding to lower and higher temperatures respectively. 1 he 
VOL. cci.—A 331. 
B 
11.3.03 
