OCT. — DEC. 1856.] 



Scientific Intelligence. 



109 



IX. Scientific Intelligence, 



[The following letters regarding Earthquakes, lately observed at Travancore, 

 are extracted from the Madras Athenceum.'] 



Sik, — Perhaps the following account of the Earthquake observ- 

 ed in Travancore on the morning of Monday the 11th instant may 

 interest some of your readers. 



The assistant in the Trevandrum observatory having the watch 

 on the morning referred to, was entering an observation when he 

 heard a low rumbling sound which he thought at first was distant 

 thunder towards the north-east; in about three seconds the raft- 

 ers of the building began to creak, the windows to rattle and a 

 mirror resting on the table to shake : he immediately looked at 

 the clock and found the time 5 h. 53 m. 30 s. which, allowing for 

 the known clock error, would give the mean Trevandrum time of 

 the commencement of the sound 5 h. 51 m. 25 s. He then went 

 out to look towards the north-east and immediately thereafter the 

 sound ceased with a louder " bom" ; on looking again at the clock 

 the time by it was 5 h. 54 m. and he estimated the duration of 

 noise and shock at nearly twenty seconds. He now examined the 

 magnetical instruments, but could perceive neither vibration nor 

 change of mean position. It is not impossible however that the 

 magnets might have had swinging or dancing motions without be- 

 ing remarked by the observer, as vibrations round a vertical axis 

 only are noted. An examination by myself since, of the observa- 

 tions made before and after the shock, confirms the fact of the 

 steadiness ©f all the magnets ; neither did I find any thing remark- 

 able in the state of the atmosphere. The velocity of the wind from 

 the north-west was nearly as usual at the same hour ; the sky was 

 nine-tenths clouded, the clouds moving from north-west; the 

 temperature of the air was nearly 73°, the maximum temperature 

 of the day being nearly 78°. 



A lady living near the observatory was awoke by a low rumbling, 

 puffing noise, which terminated by a stifled explosion, as if under 



