114 Barrett, Brown, AND Haprretp— Researches on the 
TABLE I. 
CARBON SERIES. 
| la {| Relative Conductivity. | 
| | 
| Mit, | Principal Constituents. 1 12, | Thermal. | Electrical. | 
: | 
B 99°71 Fe; 0-030, . . .| 15:0 225 100-0 100-0 
WSS | CTAiog OSC, , . «i nae 213 94-6 96:3 
IGA || OG EzONG , . .| we | wa 78°6 855 | 
1392A | 9866Fe;0850,. . .| 126 | 159 70°6 66:5 
| 1822€: || CSIs IO3G, . .  .| ix 151 671 62:0 
611 OSE 1s OSC, . . .| ie 134 | 59-6 526 
614 OCU Hog IHC, . « | ile 126 56:0 46:3 
As was stated in a previous paper, it is possible (other conditions being the 
same) to estimate the amount of carbon present in carbon steels by the electric 
conductivity of the specimen. Our results have been quoted in a recent paper by 
M. Benedicks, who has confirmed the foregoing opinion.* It would be desirable 
to repeat the experiments on electric and thermal conductivity, especially of the 
carbon steels, with specimens quenched at a definite, high temperature, for only 
thus can the true characteristics of each alloy be exhibited. A series of extremely 
pure carbon steels is now being prepared at the Hecla Steel Works; and we hope 
to repeat our experiments with these in the quenched as well as the annealed 
states. 
In Table II. are given the results with some of the manganese steels: it 
will be borne in mind that the series of specimens in each Table were tested 
simultaneously, so that they are strictly comparable. 
* T am glad to draw attention to Dr. Carl Benedicks’ valuable and laborious investigations, entitled 
Recherches physiques et physico-chimiques sur Pacier au carbone, published this year in Upsala. One portion 
of this important work, the author states, is founded on the fact that ‘la résistance électrique permet 
une évaluation exacte de la teneur en carbone de trempe.” It is by this means he arrives at the 
conclusion that the solubility of carbon in iron, when excess of carbon is present, is 0:27 per cent. at the 
ordinary temperature. Furthermore, Dr. Benedicks, by the collation of our experimental results with 
those of his own and of some others, has arrived at the important conclusion that “des quantités 
équivalentes des éléments étrangers, dissous dans le fer, causent le méme accroissement de résistance,” 
and hence gives a provisional formula by which the electric resistivity of any steel can be calculated 
when its chemical composition is known—a remarkable conclusion which awaits further verification, 
