1910-11.] On Magnetism of Copper-Manganese-Tin Alloys. 85 
Y. — On the Magnetism of the Copper-Manganese-Tin Alloys under 
varying Thermal Treatment. By Alexander D. Ross, M.A., 
B.Sc., Lecturer on Natural Philosophy in the University of 
Glasgow, and Robert C. Gray, M.A., Houlds worth Research 
Scholar, University of Glasgow. 
(MS. received June 20, 1910. Read same date.) 
Ternary Magnetic Alloys . — In 1905 investigations on magnetic alloys 
of the Heusler type were commenced in the Physical Institute of the 
University of Glasgow. The earlier tests * were carried out on an alloy 
containing about 6 25 per cent, copper and the remainder manganese and 
aluminium in atomic proportions. Towards the end of 1907 the research 
was extended to other members of the ternary system, each alloy having, 
however, the same relative proportions of manganese and aluminium, t From 
a comparison of all the data obtained, the authors were led to the view that 
the presence of Cu 3 A1 played an important part in the magnetic properties 
of these alloys.* This intermetallic compound exhibited effects of the same 
nature as did the Heusler alloys when subjected to annealing, quenching, or 
other thermal treatment. It therefore seemed not unlikely that the 
magnetism of the alloys in the ternary system was due to the entrance of 
Cu 3 A1 into solid solutions. 
Copper-manganese-tin Alloys . — The production of strongly magnetic 
materials by alloying non-magnetic elements has such an important bear- 
ing on a general theory of magnetism, that it is very desirable to 
investigate fully the various magnetic ternary systems. Several such 
groups are known, § as, for example, alloys formed by the addition of 
antimony, arsenic, boron, bismuth, or tin to manganese bronze. The 
authors have now carried out a series of tests on members of the copper- 
manganese-tin system, and it is proposed to give in this paper a general 
sketch of the results obtained. 
Scheme of Castings . — The object of the research was to ascertain the 
influence of heat treatment on the magnetism of alloys belonging to this 
* A. Gray, Proc. Roy. Soc., lxxvi., A, 271 (1905) ; A. D. Ross, Proc. Roy. Soc. Edin., 
xxvii., 88 (1907) ; J. G. Gray, ibid., xxviii., 403 (1908). 
t A. D. Ross and R. C. Gray, Proc. Roy. Soc. Edin., xxix., 274(1909). 
+ A. D. Ross and R. C. Gray, Zeit. f. anorg. Ghent., lxiii., 349 (1909). 
§ F. Heusler, Verh. d. deut. phys. Gesell., v., 219 (1903). 
