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THE EARTHQUAKE OF OCTOBER 6th, 1863. 



On the morning of Tuesday, the 6th of October, 1863, at about 20 minutes 

 past 3 o'clock, Greenwich time, the sky being then free from clouds, and the air 

 cold, calm, and clear, a very extraordinary sound was suddenly heard approaching 

 with astonishing rapidity from the Westward. 



This souna, which appeared to consist of a rapid succession of detonations, was 

 accompanied by a tremor of the ground which made the windows rattle in their 

 frames as in a gale of wind. 



Then came a very considerable lift of the ground — the true earthquake wave 

 — and, with the shock, a crash of subterranean thunder, resembling the firing of 

 a battery of heavy guns underfoot. Immediately afterwards the sound was 

 heard dying away in the distance. 



According to Daubeny, all earthquake movements, when they are anything 

 more than mere tremors, may be divided into three kinds — " the undulatory, the 

 succussive, and the vorticose." 



" Of these three kinds of earthquake shocks, the first is the most common 

 and the most harmless. From the second, that of succussion, more is to be 

 apprehended ; but the vorticose movement is the one which has been felt in the 

 most violent and disastrous catastrophies on record." (Daubeny on volcanoes, 

 c. 32.) 



The earthquake of 1S63 was one ot the first kind ; the undulation "proceeded 

 onward in a uniform direction " ,- * and thus although the shock, in this neigh- 

 bourhood, at least, was very considerable, no serious mischief followed the 

 movement. 



The exact direction of this shock is still a matter of dispute. Indeed it is no 

 easy thing to determine the course of an earthquake ; for the best constructed 

 seismometers have a serious difficulty to contend with, which is this, — there is 

 no fixed point to start from ; everything in an earthquake being alike in 

 motion. 



We must be satisfied, I think, with a rough approximation to the truth, 

 trusting almost entirely to our own feelings and those of others. 



My house faces E. S. E., the back, therefore, is turned to W. N. W. Now, 

 according to the feelings of the members of my family, the shock struck the 

 back of the house first and passed away by the front. 



Two policemen, standing at the moment of the shock at the junction of 

 Blue School and Widemarsh Streets, felt satisfied that the sound rolled towards 



* Daubeny. 



