JOURNAL OF THE COLLEGE OP SCIENCE, IMPERIAL UNIVERSITY, 

 TOKYO, JAPAN- 



VOL. XIX., ARTICLE 6. 



Modulus of Rigidity of Rocks 



AND 



Hysteresis Function. 



BY 



S. KUSAKABE, Rigakmhi. 



With Plates I — XXII, containing 53 Figaros. 



CONTENTS. 



I. Introduction. 



II. Arrangement and twisting apparatus. 



III. General investigation of the stress-strain relation. 



IV. The doubly indefinite character of the Modulus of Rigidity. 



V. Yielding and Eecovery from the yielding. 



VI. The Hysteresis Function. 



VII. Experimental verification. 



VIII. Effect of temperature. 



IX. Relation between the velocity of propagation and the amplitude of 



seismic waves. 



X. Explanation of plates. 



INTRODUCTION. 



Since Galileo Galilei } published his inquiries concerning the 

 rupture and strength of beams in 1638, the elastic nature of substances 



* Detailed descriptions of the experiments are to be found in " The Publications of the 

 Earthquake Investigation Committee in Foreign Languages," No. 14, Tokyo, 1903. 



(1) Galileo Galilei. Thomas Salisbury's Mathematical Collections and Transactions; 

 London, 1655. Vol. II. 



