538 Mr. R. Mallet on the Vorticose Movement, 



earthquake at Boston, in New England, of November 18th, 

 1755, communicated by John Hyde, Esq., F.R.S. He says, 

 "the trembling continued about two minutes; near one hun- 

 dred chimneys were levelled with the roofs of the houses, and 

 many more shattered. Some chimneys, though not thrown 

 down, are dislocated or broken several feet from the top, and 

 partly turned round as on a swivel. Some are shoved to one 

 side horizontally, jutting over, and just nodding to fall," &c. 

 This author does not seem to have been struck with this odd 

 circumstance of the twisting round of the chimneys, and offers 

 no explanation. The next instance that I have found is in 

 the account of the great earthquake of Calabria, in 1783, as 

 recorded by the Royal Academy of Naples, quoted by Mr. 

 Lyell, in his Principles of Geology, vol. i. page 482. After 

 describing several other remarkable phaenomena, tending to 

 show the great velocity of the shock, such as that many large 

 stones were found, as it were, shot out of their beds in the 

 mortar of buildings, so as to leave a complete cast of them- 

 selves in the undisturbed mortar; while in other instances 

 the mortar was ground to powder by the transit of the stone, 

 he says, " Two obelisks (of which he has given figures) 

 placed at the extremities of a magnificent fafade in the con- 

 vent of St. Bruno, in a small town called Stephano del Bosco, 

 were observed to have undergone a movement of a singular 

 kind. The shock, which agitated the building, is described as 

 having been horizontal and vorticose. The pedestal of each 

 obeli.sk remained in its original place, but the separate stones 

 above were turned partially round, and removed sometimes 

 nine inches from their position without falling." This is all 

 that Lyell says upon the subject; he contents himself appa- 

 rently with the vorticose account of the Neapolitan Academy. 



I have found some i'ew other notices of similar phaenomena 

 in old books of travels. Two additional instances, however, 

 will be sufficient. The first will be found in the quarterly 

 journal of the Royal Institution, in a narrative of the earth- 

 quake in Chili, of November 1822, communicated by F. Place, 

 Esq. 



The church of La Morceda, at Valparaiso, built of burnt 

 bricks, stood with its length north and south. [The houses 

 are built of adobes, or sun-dried bricks.] "The church 

 tower, sixty feet high, was levelled ; the two side- walls, full of 

 rents, were left standing, supporting part of the shattered roof, 

 but the two end- walls were entirely demolished. On each 

 side of the church were four massive buttresses, six feet square, 

 of good brickwork ; those on the western side were thrown 

 down and broken to pieces, as were two on the eastern side. 



