Prof. Ferrara on the Earthquakes in Sicily in 1823. 367 



immense clouds of smoke, and earthy ashes, which were ejected from 

 June to October; which covered the more lofty part of the mountain with 

 a gray stratum ; which filled the atmosphhere, and gave out throu°h the 

 whole region a strong odour of sulphur, clearly prove that all these com- 

 motions were produced by forces collected in the recesses of iEtna. 



While Nicosia and the whole space between Madonia and iEtna were 

 in such commotion, Sicily to the west, and all the northern coast, enjoyed 

 perfect quiet ; but a sad reverse was preparing. In October, iEtna ceas- 

 ed throwing out sulphurous ashes and sand, and with it ceased all its 

 noises, and shocks, and all was calm. In February, in the beginning 

 of the next year, small motions of the earth were felt along the northern 

 side of the island, which were the preludes to the scene that presented 

 itself in March. 



The direction of the motion was from N. E. to S. W. as was proved by 

 all the phenomena mentioned in the beginning. I will not be guided by 

 the injuries suffered in different parts, for these spring from a complica- 

 tion of causes ; from the soil, its greater or less capacity of receiving and 

 communicating motion ; from the manner in which it presents itself to 

 the progressive motion, and from the state of the edifices. These cir- 

 cumstances may sometimes produce anomalies which easily deceive those 

 who do not bestow in the examination of them the attention which they 

 deserve ; but without fear of error, I may say, that in general the shock 

 was much the most forcible on the northern shore, and at a little distance 

 from it; and that it went on gradually, diminishing towards the inte- 

 rior. The moving force, then, must have been in operation somewhere 

 under the sea opposite this part of the island. Naso was almost en- 

 tirely ruined ; Patti, and all the towns about Capes Orlando and Calava, 

 and which are nearer Eolia, were considerably damaged. Some very small, 

 thinly inhabited towns lost little, because they had little to lose ; others 

 were in some measure defended by their situations. Palermo, at the bot- 

 tom of a bay which curves towards these burning islands, and surround- 

 ed by large and high mountains on the other side, was exposed to the 

 whole force of the motion against it ; this it was, together with the de- 

 graded state of its buildings, which brought such ruin upon this beautiful 

 city. Every thing seemed then to announce to us, that the most expan- 

 sive vapours which proceed from the burning furnaces of Eolia, in de- 

 veloping their immense volumes, urged against the sides of those cavities 

 which once contained the matter of which all these islands are formed, 

 produced the motion that struck obliquely against Sicily, and moving 

 along the shore towards the west, spread despair throughout Palermo. 

 After the shock of the fifth, their motion was more free ; and they were 

 heard murmuring under the soil near our island, seeking an outlet from 

 the obscure caverns in which they were generated, but not propagating 

 their motion to any considerable distance. The course of that of the 

 seventh was in the same direction witli that of the fifth ; but that of the 

 thirty-first was in a direction directly opposite, since it was felt at Mcs- 

 inn, and not at Palermo. The undulations were determined by llie ho- 



