r 
54 Mr. Matter on the Dynamics of Earthquakes. 
ofthe buttresses is to be accounted for simply bya straight line movement, acting 
in connexion with the attachment of the buttresses at one side to the flank wall 
of the church. 
The last instance I shall quote is from the pages of the able and delightful 
Darwin, in his Journal of a Naturalist’s Voyage.* In describing the effects of the 
great earthquake of March, 1835, upon a building in the town of Conception; 
and, after noticing the evidences of immense velocity in the shock, by which 
the buttresses, projecting from the nave walls of the cathedral had been cut clean 
off close to the wall by their own inertia, while the wall, which was in the line of 
shock, remained standing, he proceeds: ‘* Some square ornaments on the coping 
of these same walls were moved by the earthquake into a diagonal position. A 
similar circumstance was observed after an earthquake at Valparaiso, in Calabria, 
and other places, including some of the ancient Greek temples (for which he 
quotes Arago in I'Institut., 1839, p. 337, and Miers’ Chili, vol. i. p. 392). 
« This twisting displacement,” he proceeds, “ at first appears to indicate a vorti- 
cose movement beneath each point thus affected, but this is highly improbable.” 
* Colonial Library Edition, p. 308. 
