82 Brown—The Densities and Specific Heats of some Alloys of Iron. 
TABLE XX. 
NickrL-MANGANESE STEELS. 
Percentage Composition | Specific | 
Heat | 
Mark C Ni Mn o | pxo 
lee’ Jt z 5 | 
1109 D 0-8 | 14:55 | 5:04 0-1208 0:9455 
1414A | 06 | 19-00 5°04 0-1194 0:9378 
1414 B 0°6 25°00 5°04 0°1186 0:°9402 
The three steels in Table XX. contain each a high percentage of carbon, as well 
as over 5 per cent. of manganese; and if the results are plotted on the high nickel 
part of the nickel curve in fig. 6, the points all lie above it; and they also hea little 
above the carbon curve in fig. 5. The combined action of carbon and manganese, 
no doubt, masks the effect of the nickel on the specific heat. The thermal capacity 
per unit bulk remains fairly constant, as shown in the last column of the Table. 
CONCLUSIONS. 
The following conclusions may be drawn from these experiments :— 
1. Carbon added to iron increases the specific heat by about 0:0089 per 1 per 
cent. of added carbon. 
2. Manganese, when added to iron up to about 18 per cent., increases the 
specific heat about 0:0006 per 1 per cent. of added manganese. 
3. Nickel, when added to iron up to 4 per cent., increases the specific heat 
0:0038 for every 1 per cent. of nickel added; and further additions of nickel up 
to 20 per cent. have little or no effect, whilst between 20 and 31 per cent. of nickel 
the specific heat is increased by 0-005. 
4. Tungsten, when added to iron up to 1 per cent., cuereases the specific heat 
0:0028 ; and when 3°5 per cent. of tungsten is present, the specific heat of the 
material is the same as that of pure iron; whilst a further addition of 12 per cent. 
of tungsten decreases the specific heat by 0:0093. 
5, Silicon, when added to iron up to about 2 per cent., increases the specific heat 
