72 Brown—The Densities and Specifie Heats of some Alloys of Iron. 
5. Stlicon when added to iron (up to 5:5 per cent. of silicon) zcreases the 
specific volume of the material by 0°0011 c.c. for every one per cent. of added 
silicon. 
6. Chromium when added to iron (up to about 3 per cent. of chromium) increases 
the specific volume of the material by about 0.00034 c.c. per one per cent. of 
added chromium, but a further addition of chromium—from 3 up to 9°5 per cent. 
—has no effect on the specific volume of-the alloy. 
7. Copper when added to iron (up to about 1°5 per cent. of copper) decreases 
the specific volume of the material about 0:0005 ¢.c. for every one per cent. of 
added copper; but the specific volume of the alloy is not appreciably changed by 
further additions of copper up to about 4 per cent. 
8. Cobalt when added to iron (up to 7 per cent. of cobalt) decreases the 
specific volume of the material by 0:0001 ¢.c. for every one per cent. of added 
cobalt. 
9, Aluminium when added to iron (up to 4°5 per cent. of aluminium) zereases 
the specific volume of the material by 0:0025 c.c. for every one per cent. of 
aluminium added. 
Taking the specific volume of pure iron as 0:1269 ¢.c., the effect of adding 
an element to iron is exhibited in the following table. 
In column A is given the change in the specific volume of the material 
obtained by adding one per cent. of an element to 99 per cent. of iron, assuming 
that no change takes place in the specific volumes of the constituents ; the sign (+) means 
that the resultant specific volume is greater than, and (-) means that it is less 
than, the specific volume of pure iron, viz.: 0°1269 ¢.c. Column B gives the 
corresponding values obtained from these experiments. 
| Namerctillomont Calculaied Opsstyed MS 
| Carbon + 0:00308 c.c. + 0:0018 c.e. 0:00128 c.c. 
Manganese + 0:00008 ,, + 0:00026 ,, 0:00018 ,, 
Silicon +0:0029 _,, } oe COKOLIL 0:0018 _,, 
Chromium + 0:00027 ,, + 0:00034 ,, 0:00007 ,, 
Aluminium + 0:00258 _,, + 0:0025 ,, 0:00008 _,, 
Nickel — 0:00014 ,, — 0:00008 ,, 0:00011 ,, 
Tungsten —0:00075 ,, — 0:0009 ,, 0:00015 _,, 
Copper —0:00015 ,, — 0:0005 _,, 0:00035 _,, 
Cobalt —0:00011 ,, | _ 0-001 - 0:00001 _,, 
