DEVEL OFMEiVT OF SEISMOL OG V hV JAPAN 305 



electrical condiictivity. Tliey also made an observation of the actual 

 temperature of lava in tlie ci-ater of Mt. Mihara, l)v means of an 

 optical pyrometer. 



The melting points of some Japanese minerals have been deter- 

 mined by Y. Yamashita and M. Majima/'^ Different thermal proper- 

 ties have been investiguted by A. Tadokoro/-^ On the other hand, 

 researches into the different physical properties of Japanese minerals 

 have been carried out by S. Kozu*:"^ and his collaborators. All tliese 

 reports were contributed by the Tohoku Imperial University. In this 

 connection, T. Okaya's'^'') determination of the sjecific heats of different 

 specimens of rocks may also be mentioned. 



We may here also cite a very original investigation by S. Suzuki^^^ 

 of the number of pieces into which a plate of some brittle substance 

 was broken. This field of resepa-ch appears the more interesting witli 

 respect to the recent investigations into the mechanisms of earthquakes 

 by S. Fujiwhara, S. Ono, and others, already cited. Lastly, we may 

 mention a pajier by Suzuki on the age of the earth/^^ His theory is 

 based on the assumjition that the heat loss is covered by the liberation 

 of the latent heat of the solidifying crust, neglecting the effects of 

 shrinkage and of radioactive minerals. The age thus estimated turns 

 out to be of the same order of magnitude as that obtained by other 

 methods. 



Practical Sides. 



As is fully implied by the proper name of the E.I.C., Sinsai-yoho- 

 tyosakivai ( literally committee for investigating the prevention of 

 earthquake damage.), the jwactical application of Feismology, especially 

 in alleviating the woeful disasters due to the natural calamity, has 

 been one of the immediate aims of the Committee. From the earliest 

 date of its existence up to the present day of its dissolution, the 



(1) Sci. Rep. Toh., [i] 2 (1913), 175. 



(2) Sci. Eep. Toh., [i] 10 (1921), 339. 



(3) Sci. Rep. Toh., [iii] 1 (1921-23), 1, 19, 25, 233; 2 (1924-25), 1, 9, 187, 203 

 Jap. J. Astr. Geophys., 2 (1924), 107. 



(4) Jap. J. Astr. Geophys., 3 (1925), 45. 



(5) N.S.B.K., [iii] 3 (1921), 1G8. 

 (6 T.S.B.K., 6 (1912), 204. 



