84 Brown—The Densities and Specific Heats of some Alloys of Iron. 
TEMPERATURE RISE IN DEGREES CENTIGRADE DUE TO HYSTERESIS IN ONE HOUR. 
| Induction = 16000 c.g.s. Induction = 6000 c.g.s. 
Frequency = 20 per sec. Frequency = 50 per sec. 
ork | Peincnat, | GEROEY, | Temperatume | GENET, | Temperature 
onstituent per cycle Rise per cycle | Rise 
Sb CL IL 0:028 C 10000 19°C 1908 9:2°C 
B. 0:03 C 11000 21 2090 10:2 
L.S.S. 0:05 © 11460 22 2180 10°5 
611 0:58 CO 22810 43 4620 21:7 
48 0:50 Mn 20460 38 2290 18:4 
4147 1:00 Mn 23080 44 4710 22:5 
1287 D 1:92 Ni 15750 29 3050 14-2 
1287 E 3:82 Ni 16300 26 3086 14:3 
1294 F 1:00 W 14580 31 2865 13°38 
1294 H 3°50 W 25800 48 5170 24:3 
1167H 2:25 Al 10950 21 | 2170 10°6 
898 EB 5:50 Si 6500 12 | 1290 6:2 
In both cases the advantage of the silicon iron or steel over pure iron is shown 
by these results. A silicon iron is now extensively used for armature and trans- 
former cores, and is known commercially as Stalloy. For sheets of thickness 
0356 mm. the energy loss at an induction of 6000 c.g.s. lines and frequency 50, 
is 0°38 watt per lb. as compared with 0°58 watt per lb., the value for practically 
pure iron under the same conditions. 
As far as I know, the chemical composition of Stalloy has not yet been made 
public; but from the tests which I recently made of the specific volume of this 
material, I should say that it contained about 3°3 per cent. of silicon. 
In conclusion, I beg to state that my best thanks are due to Professor Barrett, 
F.R.S., who has afforded me every facility for carrying on this work in a 
Laboratory where space for private research is very limited. 
ROYAL COLLEGE OF SCIENCE, 
DUBLIN. 
