Brown—The Densities and Specific Heats of some Alloys of Tron. 77 
TABLE XIII. 
NickrEL STEELS. 
Percentage Composition Specific 
Heat 
Mark C | Si | Mn | Ni c exe 
1397 B 0:26 | 0:38 0:18 0°58 0-1156 0:9051 
1287 D 0-14 0:21 0-72 1:92 O-1171 | 0-9218 
1287 E 0-19 0:20 0°65 3°82 01180 0:9271 
1447 A 0°81 | 0:39 0-61 12°70 01170 09120 
1287K | 0-19 0:27 0:98 19°64 0:1157 0:9124 
1287 L 0°16 0°30 | 1:00 24-51 01170 09282 
1449 A 0-70 =| 0:82 31°40 01209 0:9707 
In Table XIII. are given the specific heats and thermal capacities of the seven 
nickel steels, and in the nickel curve fig. 6 the specific heats are plotted against 
the percentage amounts of nickel present. From the curve it will be seen that 
the specific heat of the alloy is ereased up to about 4 per cent. of nickel present ; 
then a slight decrease occurs until about 20 per cent. of nickel is reached; then up 
to about 31 per cent. the specific heat is again mereased. 
This point of flexure in the curve of the nickel steels, when about 20 per cent. 
of nickel is present in the iron, occurs in the case of the other physical properties 
of these specimens so far tested, viz., in the electrical, the magnetic, and the 
mechanical,* as well as in the density. 
By comparing the first specimen in ‘Table XIII. with the pure iron 8.C.I. in 
Table XI., we see that the first addition of 0°58 per cent. of nickel to the iron 
increases the specific heat of the material by 0:0022, or at the rate of about 
0:0038 for every 1 per cent. of added nickel; and comparing the two specimens 
containing 0°58 per cent. and 3°82 per cent. of nickel respectively, it will be seen 
that the addition of 3°24 per cent. of nickel increases the specific heat by 0:0024. 
By comparing the specimens marked 1287 E and 1287 K it is seen that the 
addition of about 16 per cent. of nickel decreases the specific heat 0°0023, and 
between 20 and 31 per cent. of nickel, the specific heat is increased by 0-005. 
The last column in Table XIII. shows that the presence of about 31 per cent. 
of nickel increases the thermal capacity per unit volume by about 6°75 per cent. 
* Scient. Trans. Roy. Dublin Soc., 1900, vol. vii., pp. 111, 112. 
O 2 
