ON SEISMOLOGICAL INVESTIGATION. 



Catalogue of Earthquakes — continued. 



137 



» other shocks were :— Yokohama, Ih. 17m. 39s., slight; Yokosuka, Ih. 17m. 30s., weak; Mai- 

 •bashi, Ih. 30m. 03s., slight; Gifu, Ih. 20m. 46s., sUght. This shock is supposed to represent a landslip 

 .in the Bay of Tokio, for it only extends round ToMo. 



III. On the Installation and working of Milne's Horizontal Pendulum. 

 By John Milne, F.R.S., F.G.S. 



General Remarks. — As it has been established that the movements re- 

 sulting from a large earthquake originating in any one portion of our globe 

 can, with the aid of suitable instruments, be recorded in any other portion 

 of the same, the Seismological Committee of the British Association have 

 asked for the co-operation of observers in various parts of the world in an 

 •endeavour to extend and systematise the observation of such disturbances. 

 The first object in view is to determine the velocity with which motion is 

 propagated round and possibly through our earth. To attain this, all 

 that is required at a given station is the times at which various phases of 

 motion are recorded, for which purpose, for the present at least, an instru- 

 ment recording a single component of horizontal motion is sufficient. 

 Other results which may be obtained from the proposed observations are 



