HERTFORDSHIRE EARTHQUAKES. 



161 



blackness enveloped the mountains, gradually extending to the 

 zenith. About 4 p.m., thunder was heard at an immense 

 height overhead, and at the moment of the strongest electric 

 explosion, at 4.12, there were two earthquake shocks with an 

 interval of 15 seconds between them, the first being preceded by 

 a very violent blast of wind followed by electrical rain falling in 

 great drops. 



As these earthquakes were not very severe ones, Mallet's brief 

 account, from one of Perrey's Memoirs, may be quoted as an 

 example of a more disastrous and more recent convulsion. 



1837, Sept. 22, 3 a.m. Van Dieman's Land and New 

 Holland. "Violent and disastrous earthquake, which continued 

 until dawn. The sea made inroads upon the shore, and a new 

 island was formed. On the evening of the 21st, terrible 

 explosions were heard at Lasaya, and long luminous streaks of 

 bright red were seen on the horizon, the whole sky then became 

 of the same colour. During the earthquake the surface of the 

 ground was in motion like that of the waves of the sea, while 

 every five minutes the explosions became terrible. The 

 atmosphere was heavy, and was lit up by flashes of lightning. 

 Lasaya and Maya were thrown down and filled with corpses. 

 A terrible tempest at the same time." 



We may be thankful that such a catastrophe as this is not 

 likely to occur in our country, and I think we should be con- 

 vinced that the aerial disturbances which so often accompany 

 earthquakes are not always mere coincidences. 



3. Recent Records. 



It may perhaps be objected that all these are old records, and 

 that we have, therefore, no means of verifying them. The last 

 British earthquake, which occixrred dm-ing tempestuous weather, 

 seems to have been accompanied by a display of electric energy 

 somewhat different from a thunderstorm. The following 

 account of it appeared in the ' Morning Post ' of the 4th of 

 January, 1907 :— 



" Earth tremors varying in intensity were felt on Wednesday 

 night (2nd) in the higher parts of Newport, Monmouthshire. 

 A loud, rumbling noise at a quarter to eleven o'clock was 

 followed by a distinct movement of the earth and the violent 

 shaking of windows, some of which were broken. A quarter of 

 an hour later there was another but less severe shock. The 

 tremors were registered on scientific instruments in the town, 

 and were distinctly felt by many persons; children were 

 frightened as they lay in bed, and others complained of 

 a feeling of sickness. Some persons state that the rumbling 

 was followed by flashes as of lightning, and so extraordinary 

 was the noise that residents left their houses in alarm to 

 ascertain whether their neighbours had been similarly dis- 

 turbed." 



The expression " flashes as of lightning" is very suggestive in 



