88 Proceedings of the Royal Society of Edinburgh. [Sess. 
Apparatus . — The tests were performed on a Gray-Ross magnetometer.* 
For the measurement of the magnetic quality at temperatures above the 
normal, the specimens were placed in an electric furnace of the newest type f 
for use within the magnetising solenoid. By this means the alloys were 
raised to temperatures approaching a red heat without danger of oxidation. 
The temperatures employed in the tests were measured by two thermo- 
elements consisting of wires of platinum and platinum-iridium enclosed 
in tubes of fused quartz. The instruments were calibrated before and after 
the tests by determination of five freezing and boiling points, and were found 
to have remained unchanged during the interval. 
Composition of the Alloys . — The alloys employed were found on subse- 
quent analysis to have the compositions given in Table I. The first column 
gives the approximate tin content of the alloys, and the various materials 
Table I.— Analyses of the Alloys. 
Designation of the Alloy. 
Percentage Composition. 
Cu. 
Mn. 
Sn. 
14 per cent, tin . 
60-2 
25-1 
14T 
16 „ „ . . . 
58*7 
24-5 
16*1 
18 „ „ 
57-6 
239 
18-0 
30 „ „ . 
49*2 
20*4 
29*8 
38 „ „ . . 
43-4 
18-1 
38-0 
48 „ „ . 
36-4 
15-0 
48-1 
will hereafter be designated by these names. The amount of iron present 
in the alloys varies with the manganese content, being introduced as an 
impurity in the manganese. Its amount is always small, never exceeding 
a half per cent. 
Tests on the Alloys as Cast . — The rods of the alloys in the form of 
cylinders measuring 20 x 1T5 cms. were first of all tested in the condition 
as cast. No preliminary dressing operations were performed with the ex- 
ception of the removal of the end portions. As the metal was hard and 
brittle, this could be done by a tap with a hammer and chisel, the specimen 
being supported on a second chisel at the point where the fracture was 
desired. The alloys broke with a clean fracture and the metal was white 
and lustrous. Table II. gives in outline the results of the magnetic tests, 
on a specimen of each of the various alloys. 
* J. G. Gray and A. D. Ross, Proc. Roy. Soc. Edin., xxix., 182 (1909). 
t J. G. Gray and A. D. Ross, Proc. Roy. Phil. Soc. Glasg., xli., 84 (1910). 
