1835.] LINES OF VIBRATION. 295 



tended iii a S.E. and N.W. direction, and therefore corresponded 

 to the lines of undulation or of principle flexure. Bearing in mind 

 all these circumstances, which so clearly point to the S.W. as the 

 chief focus of disturbance, it is a very interesting fact that the 

 island of S. Maria, situated in that quarter, was, during the general 

 uplifting of the land, raised to nearly three times the height of any 

 other part of the coast. 



The different resistance offered by the walls, according to their 

 direction, was well exemplified in the case of the Cathedral. The 

 side which fronted the N.E. presented a grand pile of ruins, in the 

 midst of which door-cases and masses of timber stood up, as if 

 floating in a stream. Some of the angular blocks of brickwork 

 were of great dimensions ; and they were rolled to a distance on 

 the level plaza, like fragments of rock at the base of some high 

 mountain. The side walls (running S.W. and N.E.), though ex- 

 ceedingly fractured, yet remained standing; but the vast buttresses 

 (at right angles to them, and therefore parallel to the walls that 

 fell) were in many cases cut clean off, as if by a chisel, and hurled 

 to the ground. 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, Calabria, and other places, including some of the 

 ancient Greek temples.* This twisting displacement, at first ap- 

 pears to indicate a vorticose movement beneath each point thus 

 affected ; but this is highly improbable. May it not be caused by 

 a tendency in each stone to arrange itself in some particular posi- 

 tion, with respect to the lines of vibration, in a manner somewhat 

 similar to pins on a sheet of paper when shaken? Generally 

 speaking, arched doorways or windows stood much better than any 

 other part of the buildings. Nevertheless, a poor lame old man, 

 who had been in the habit, during trifling shocks, of crawling to a 

 certain doorway, was this time crushed to pieces. 



I have not attempted to give any detailed description of the 

 appearance of Concepcion, for I feel that it is quite impossible to 

 convey the mingled feelings which I experienced. Several of the 

 officers visited it before me, but their strongest language failed to 

 give a just idea of the scene of desolation. It is a bitter and 

 humiliating thing to see works, which have cost man so much time 



* M. Arago in L'Institut, 1839, p. 337. See also Micro's Chile, vol. i. 

 . "92 ; also Lyell's Principles of Geology, chap, xv., book ii. 



