xx President's Address 



and on one occasion during a strong tremor the surface of 

 these flats was seen to be agitated as by a series of very 

 short waves passing over it. I extract the following from 

 notes furnished me by Mr. Grant : — "25th July. — Barometer, 

 3005. Fine and clear. 4.40 a.m. a shock, and 10.34 a.m. a 

 moderate shock. This shock caused apeculiar vibration of small 

 ferns and under-scrub. They commenced to tremble quickly 

 at first, but increased in intensity till the maximum of the 

 shock, when the vibration died away as the wave passed 

 over. It did not appear to affect the large trees or moderate- 

 sized saplings, only the herbage close to the ground. This 

 was the first time I observed the phenomena. Again, on 

 11th August, at 2.41 p.m., during a slight shock, preceded 

 by a loud rumbling, no vibration of the ground was felt, but 

 the smaller or ground herbage was seen to tremble, the 

 motion proceeding from north-east to south-west ; the 

 loftier scrub and trees showed no motion." Another 

 gentleman, who is strongly of opinion these disturbances 

 are superficial, and not subterranean, states that he has 

 spent much of his time below ground during the last twelve 

 months at Mount Victoria (North-east Tasmania), but during 

 all the tremors and earthquakes he never felt the slightest 

 indication of a tremor under the surface. He has heard 

 the rumbling noise near the surface in the shaft, but felt no 

 vibration. He says that his companions on the surface 

 have frequently hailed him to tell him an earthquake was 

 passing, but failed on every occasion to discover any vibra- 

 tion or tremor underground, though sufficiently near the 

 surface to hear the rumbling noises. Commander Shortt, of 

 Hobart, informs me that the ship " Helena" felt the shock of 

 13th July, 150 miles to the. eastward of Cape Barren Island, 

 and that the water around her appeared convulsed. The 

 collected observations of 13th July, and of the severer shakes 

 since, make it pretty certain the direction of the seismic 

 waves has been always from north -north-east to south-west 

 in Tasmania, and from south to north on the Australian coast. 

 This seems as if the waves radiated from a centre either in or 



