Mr. Mallet's Xotice of the British Earthquake of November 9, 1852. 407 



roctions almost opposite, at the same moment, in places not far apart, and this 

 circumstance constitutes one of the dilliculties of disentangling the true elements 

 of almost every shock, and of the construction of seismometrical instruments. 



Some very local points of greater disturbance were observed. Thus, at 

 Castle Howard, in the Vale of Avoca, county of Wicklow, Ireland, the shock 

 was experienced with great severity, due to the circumstances of its position. 

 It stands upon a spur of mountain jutting out towards the westward from a 

 north and south range. It rests on slate rocks, having a generally north and 

 south strike, and its elevation on the hill is considerable. A shock from south 

 to north would therefore affect it with exaggerated power. The shock was 

 not felt at all by any one on board any of the steam-vessels passing either way 

 between Liverpool or Holyhead and Dublin, on the night of the 9th November. 

 nor was it felt by the printers up and at work in the several newspaper offices in 

 Dublin, Liverpool, or Manchester. In all these cases the local vibrations going 

 on by the machinery at work obviously prevented the earthquake jar being ob- 

 served, or confounded it with those taking place from the local causes. 



A few of the more remarkable secondary effects observed may be noticed. 

 The flickering of the gas-lights in the streets of Dublin, observed by the writer 

 from Christ-Church-place (see ante)^ occurring some minutes after the shock, 

 was doubtless due to the depression of the gasometers at the gas-works into 

 the tanks by the vertical direction of the shock, and by the surging of the water 

 in the tanks themselves, the time that elapsed being that necessary to transmit 

 siich disturbance from the gasometers through the elastic fluids in the street 

 mains, tubes, (S:c., to the lights. 



Very many small birds, chiefly sparrows, were found dead upon the ground 

 on -the morning after the shock, as at the goods sheds of the King's-bridge Ter- 

 minus, Great Southern and Western Railway, and in Mountjoy-square. This, 

 which has been often observed in earthquake countries, is due to the creatures 

 being shaken while asleep off their roosting-places, the involuntary muscles of 

 the claws, which hold them on, not being prepared to resist so sudden and 

 unexpected a shock. 



Clocks were stopped in some places, unfortunately without the time of stop- 

 ping being noted. 



As the relations of earthquakes with meteorology are as yet uncertain, it 

 appeared desirable to obtain returns on this subject from several stations within 



