Brown—The Densities and Specific Heats of some Alloys of Iron. 63 
corrected specific volumes as ordinates, it will be found that the specific volume 
of the material is slightly cxereased up to about 2 per cent. of manganese added, 
and after that the specific volume is steadily decreased. 
This curve will show that up to about 2 per cent. of added manganese the 
specific volume of the material is increased about 0°00026 for every 1 per cent. of 
manganese present. 
The specific volume of the alloy—corrected for carbon—when 18°5 per cent. 
of manganese is present, is 0°1240 ¢.c.; and hence between the limits of 4 and 
18-5 per cent. of manganese the specific volume of the material 1s decreased at the 
rate of about 0-00015 c.c. for every 1 per cent. of manganese added. 
Tasxe ILI. 
NICKEL STEELS. 
Percentage Composition Specific Volume 
Mark C Si | Mn | Ni Density Observed | Calculated Difference 
1397 B 0:26 0°33 0:18 0°58 7°8294 0:127738 0:12859 — 0:00086 
1287 D 0:14 0°21 0:72 | 1-92 7°8675 0:12711 0°12771 — 0:00060 
1287 E 0-19 0:20 0°65 | 38°82 7°8570 0°12727 0:12757 — 0:00080 
1447 A 0°81 0°39 0°61 12°70 7°7952 0:12828 0°12874 — 0:00046 
1287 K 0:19 0:27 0:93 19°64 7'8860 0:12682 0:12550 + 0°001382 
1287 L 0:16 | 0:30 LO) |}, BAboHil 7°9335 0:12605 0°12479 + 0°00126 
1449 A 0-70 0:82 | 31°40 8:0286 0°12456 0°12457 0:00000 
In Table III. are given the results for seven nickel steels which contain from 
0:58 to 31°4 per cent. of nickel, and from the columns of specific volume it will be 
observed that the addition of nickel to iron up to about 12 per cent. causes a 
contraction in the specific volume of the alloy ; whilst at about 20 per cent. of 
nickel present a distinct expansion takes place, and when there is 31:4 per cent. of 
nickel present, the calculated specific volume is practically the same as that 
obtained by experiment. 
In fig. 1 (page 64) are plotted the percentage amounts of nickel present as 
abscissee, and as ordinates the observed values of the specific volumes, as well as the 
values corrected for carbon and silicon, the effect of manganese being neglected. 
It will be seen from the curve that. the specific volume of the material is at first 
