ON THE FACTS OF EARTHQUAKE PH^ENOMENA. 313 



rocks, coloured blue ; 2, older stratified and carboniferous rocks, coloured 

 /dark gray ; 3, secondary rocks, from carboniferous to cretaceous inclusive, 

 coloured green ; 4, the tertiary formations, coloured yellow ; 5, allu vial plains, 

 detritus, &c., coloured brown; and 6, igneous rocks, modern porphyries, 

 diorites, &c., coloured red. The data have been principally derived from 

 Johnston's ' Physical Atlas,' and no attempt at exact definition of boundary 

 has been attempted, the object in view being to give some notion of the 

 class of formations through which the ranges of the shocks now about being 

 mentioned lay. 



The places at which the shocks were felt and recorded are marked along 

 with some of the greater physical features of the country, and the observed 

 directions of the shocks are marked by arrows. 



The first Indian earthquake referred to is that of June 16, 1819, the 

 night on which Cutch was wholly destroyed, the Run of Cutch submerged, 

 and the great Ullah Bund (a vast elevated bank of sand and slob) thrown 

 up ; there were two great shocks, which were felt more or less almost over 

 all Central India. 



On the same night, with the same interval of two minutes between them, 

 two slight shocks were felt at Calcutta upon the opposite side of that great 

 continent, where they were suflftcient to cause suspended lamps, &c. to vibrate. 

 These, there can be no rational doubt, were due to the same original impulse 

 that produced such devastation at Cutch more than 1000 miles off". 



They were observed at Calcutta at half- past eight o'clock, which is 90 

 minutes later than the great shocks were noted at Cutch. The distance on 

 a great circle is about 1200 statute miles, which reduced gives a transit rate 

 of only 13*33 miles per minute (Roy. As. Journ. vol. ix. p. 70). 



A considerable distance at both extremities of this long range consists of 

 loose diluvial material of the lowest possible transit coefficient, but a large 

 portion of the central tract traversed appears to consist of formations pos- 

 sessing a much higher elasticity. 



On the 26th of August, 1 834, the great earthquake of Nepaul occurred, 

 which convulsed the whole of that region, and was felt throughout the Pun- 

 jaub and over a large part of central India. No important information has 

 been obtained as to its phaenomena nearer to its probable origin, which appears 

 to have been somewhere in Thibet or Lassa, to the north and east of the 

 Himalayan chain. The Journ. Roy. As. Soc. vol. xiii. p. 158, contains a 

 summary of the events as experienced in Nepaul, where it seems to have been 

 very formidable. The direction there generally appeared to be from N.E. 

 to S.W. 



The principal shocks were at 6 o'clock p.m.; half-past 6 o'clock; half-past 

 1 1 o'clock ; and 55 minutes past noon, all Calcutta time ; and vibrations were 

 almost continuous the whole day (24' hours) of the 26th of August, 1834 ; in 

 1829 such vibrations continued for 40 days or more. 



Dr. Campbell, at Katmandu, says, " The shock at 6 o'clock lasted about 

 40 seconds ; its sound was like that of heavy ordnance passing over a draw- 

 bridge rapidly." " I felt that it was travelling with the speed of lightning 

 towards the west and just under my feet;" "trees waved to the roots as it 

 passed." Dr. C. was at the time at his house on the hills, about a mile away 

 from Katmandu, the capital of Nepaul ; and at the coming on of the third 

 shock, the murmured prayers of the vast multitude in the city reached his 

 ear with a terrible sublimity like the voice of many waters; above 100 

 houses were levelled there in a moment. All the shocks seemed to come 

 from the E. and N.E. 



Places to the east of Katmandu suflTered still more; at Bhatgaun 1000 



