On Volcanos and Earthquakes. 21 



The same in the Island of Madeira^ Nov. Ist, 1755. Df. Thomas 

 Heberden. Phil. Tr. vol. 49, 

 " At half an hour past nine o'clock in the morning was felt a 



shock of an earthquake In the northern part of the island, the 



inundation has been more violent; the sea there retiring at first 

 above one hundred paces, and suddenly returning overflowed the 

 shore " 



The same at JVeufchatel^ in Switzerland, Nov. 1*^, 1755. Mr, Pan' 



trovers. 



*' The dreadful earthquake has been perceived even in this 

 country ; it swelled our lake to the height of near two feet above 

 its natural level " 



The same at Lyons, in France, Nov. 1st, 1755. Mr. Trembley. 

 Phil. Tr. vol. 49. 



''It is said that the waters retired for some moments at the 

 end of the lake of Geneva, and that a motion was observed in 

 those of the lake of Zurich " 



Agitation of the Waters. Nov. 1st, 1755. John Pringle. Phil. 



Tr. vol. 49, 

 " About ten o'clock of the forenoon, at a seaport on the Frith 

 of Forth, about seven miles higher up than Leith, the water was 

 observed to rise very suddenly, and return again with the same 

 motion ; and this continued for three or four minutes, it being 

 then calm; but after the second and third rush of water, it was 

 always less." 



We have expatiated with some details upon the dreadful 

 earthquake which was so fatal to Lisbon in 1755, destroyed 

 whole cities in Europe and in Africa, cost the lives perhaps 

 of one hundred thousand human beings, and was felt upon 

 a surface of more than one million square miles at the same 

 moment. We have taken into consideration particularly its 

 effects upon the water of the sea. The detonation took place 

 under ground, or rather under the sea, in that space which 

 we suppose filled with condensed air, below its inferior level. 

 If we should wish to locate precisely the centre of concus- 

 sion, judging from its intensity and direction, it seems to be, 

 between the Azores, Madeira, and the continent. The sea 

 was sw elled at the same moment from the thirtieth degree of 

 latitude to the fiftieth, that is to say, on the coast of Africa 

 from Morocco up to Tangier, on the coasts of Spain and 



