THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE II. VOL. IX. 



No. XI.— NOVEMBER, 1882. 



OI^IC3-I^:^^.A.Xi .^i^TioXiiES. 



I. Earth-Movements, — Tremors and Pulsations. 



THE subjoined communication, which appeared in the columns of 

 the Times, for October 11th, from Professor John Milne, 

 E.G.S., of the Imperial College, Tokio, Japan, is of so much im- 

 portance to Physicists and Geologists all over the world, that we 

 should be negligent in our duty to our readers did we not specially 

 call their attention to it. It is easily to be conceived that, in a 

 country like Japan, where Earth-Movements and Earthquakes are 

 of constant occurrence and alarming in magnitude, the Government 

 and the people alike see the vital importance of studying their 

 attendant phenomena, and whether in building houses, chimneys, 

 laying pipes and drains, they are glad carefully to consider how 

 practically to guard these against destruction by this common form 

 of dislocatory disturbance. A Society known as the " Seismological 

 Society of Japan " has been established by Prof. J. Milne some two 

 or three years since in Tokio, and publishes a most excellent journal ; 

 and all scientific men, are invited to co-operate in making seismo- 

 logical observations. Hitherto, disturbed areas, where earthquake- 

 movements are developed in intensity, have alone been carefully 

 studied and their phenomena recorded ; but Prof. Milne's aim is to 

 demonstrate, that, by the use of delicate instruments, the most stable 

 areas in the world can all be shown to be subject to more or less 

 sensible tremors and pulsations of the solid crust, and that it is the 

 duty of all scientific men, who can command the use of suitable 

 appliances, and delicate test-apparatus, to examine into, collect and 

 record these more minute, but none the less important and measur- 

 able strains and earth-throbs. 



If we could penetrate some silent umbrageous recess in a tropical 

 forest, and could there have conveyed to us by a microphone all 

 the to us inaudible sounds going on around, our brain would be 

 stunned by the vast pulsations of animal and vegetable life throb- 

 bing everywhere — the rushing sap in the trees, the bursting buds, 

 the growing plants, the busy insects — in fact all sounds of life 

 would be transmitted to our sharpened hearing in a torrent of 

 audible vibrations. 



If, instead of contemplating the pulse-throbs of organic beings, we 

 could cause our microphone to bear upon the ground beneath us, we 

 should speedily be aware that the inorganic materials of which our 

 globe is composed are also in a state of unrest, sufiering slowly 

 everywhere from pressures, strains, dislocations, and displacements, 

 giving rise to earth- currents, tremors, and other indications of dis- 



DECADE II. — YOL. IX.— NO. XI, 31 



