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LXV. On the Variation of Thermal Conductivity during the 

 Fusion of Metals. By Seibei Konno *. 



§ 1. Introduction. 



ACCORDING to the electron theory the ratio of the 

 thermal and electric conductivities of metals is in- 

 dependent of the nature o£ the materials and proportional 

 to the absolute temperature. The experimental investiga- 

 tions | o£ different steels and iron alloys — such as carbon 

 steels, iron-nickel, iron-cobalt, and iron-manganese alloys — at 

 ordinary temperature shows that the said ratio is roughly 

 the same for these steels and alloys, notwithstanding a large 

 divergence in the respective values of the two conductivities. 

 That is, the variation of the thermal conductivity of iron 

 along with the concentration of the other components is 

 similar to that of the electric conductivity, so that we can 

 approximately expect the magnitude of one variation from 

 the other. It was also found that in the case of carbon 

 steels the above relation holds good for different high tem- 

 peratures up to 900° C, and also that the proportionality 

 between the said ratio and the absolute temperature is fairly 

 well satisfied. It has been shown by E. F. Northrup J and 

 H. Tsutsumi § that the electric conductivity of different 

 metals makes a conspicuous abrupt decrease during melting, 

 with the exception of bismuth and antimony, in the case of 

 which an abrupt increase of conductivity is observed. It 

 was therefore thought very desirable to see, whether up to 

 a temperature beyond the melting-point, a similar relation 

 exists between the two conductivities. The present investi- 

 gation was carried out on the one hand to test this relation, 

 and, on the other hand, formed a preliminary experiment 

 for studying the conductivity of molten steel, which has 

 a very great importance in connexion with the metallurgy 

 of iron. 



As to the change of thermal conductivity of different 

 substances during melting, a few experiments have been 

 made. Bams || first made an experiment with Thymol, and 

 found that the thermal conductivity of the substance 



* The thirtieth report of "The Alloy Research Institute." Communi- 

 cated by the Author. 



t Sci. Rep. vi. (1917) ; vii. (1918). 



% Jour. Frank. Inst, clxxv. p. 153 (1913) ; clxxvii. pp. 1, 287 (1914) ; 

 clxxviii. p. 85(1914). 



§ Sci. Rep. vii. p. 93 (1918). 



|| Phil. Mag. xxxiii. p. 431 (1892). 



