406 Mr. Mallet's Notice of the British Earthquake of November 9, 1852. 



strong oscillations shook all the edifices. The people immediately sallied out 

 of their houses, and sought refuge at La Alameda and in the public squares. 

 Fortunately, the shock was not renewed. The temperature was suffocating ; 

 the cloudy aspect of tlie sky induced a belief that another earthquake would 

 take place the following night. Many families accordingly retired on board 

 the vessels in the harbour. The shock was preceded by a loud noise." — " Times" 

 Newspaper, 10th November, 1852. 



The date actually referred to will be the 7th or 8th of the month. 



It may be remarked, that the basin of the Greek Archipelago appears to 

 have been in activity a little before the same period, an earthquake having 

 overthrown the magnificent columnar remains of the Temple of Jupiter Olym- 

 pias at Athens. ("Times," 24th November, 1852.) 



As respects the time of the shock, it appears to have been felt almost, if 

 not altogether, sinndtaneously over the whole area shaken in Great Britain and 

 in Ireland, — a circumstance in itself corroborating the evidence for the consi- 

 derable angle at which it emerged, for shocks nearly horizontal are always 

 observed to have a progressive translation over the shaken country. 



There is no evidence of a sufficiently precise character to warrant any con- 

 clusions, either as to the velocity of emergence of the wave, or as to its altitude, 

 i. e. the actual range of shaking produced at any point by the shock. Com- 

 paring the evidences of disturbance in Dublin and other places, with the effects 

 of many other earthquakes, the author is disposed to attribute the safety from 

 serious calamity fortunately experienced by us, in great measure, to the vertical 

 element in the direction of the shock, which, with only the same velocity and 

 range, had it been been much more nearly horizontal, might probably have pro- 

 duced great disaster. 



On examining the lines of horizontal direction for different localities as 

 recorded on the map, they will be found to differ considerably. In this there 

 is nothing unusual or irreconcilable with faithful observation or with science. 

 Local changes in the true direction, and still more in the apparent or horizontal 

 direction, of translation of tlie earth-wave are due to many causes, principally to 

 changes in the geological formations at different points, or to the structure of 

 the earth's crust, and to abrupt changes in the physical features of the surface 

 of the country. Instances are not wanting of the same shock being felt in di- 



