'which ocairred in Sicily in March 1823. "175 



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, vEtna ceased throwing out sulphurous 

 ashes and sand, and with it ceased all its noises and shocks, 

 and all was calm. In February at 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 phaenomena mentioned in the beginning. 

 I will not be guided by the injuries suffered in different parts, 



journals, which say, that in the recent eruptions of jEtna the earth opened at 

 a great distance from the crater, and that a muddy substance which is not 

 lava was thrown out. As this important error, should it gain credit, would be 

 injurious to science, I make all haste to correct it. In 1822, neither at a great 

 nor at a small distance from the crater, the earth opened, .ind the matter 

 thrown out is volcanic ashes, perfectly like that which has usually been ex-- 

 pelled by this volcano ; at least for the forty years that I have studied it. It 

 did not come out in the form of mud, but in exceedingly fine dust, which 

 afterwards became wet with the vapour condensed within the very edges of 

 the fissures, or which fell in brine. It is a long while since any of the writers 

 on volcanos, wishing to establish the theory of " eruptions of mud," have 

 named that of sea-water and shells in 1755; a popular credulity, which I 

 have been compelleil to do away by every possible proof. This new error 

 of 1822 might recall their arguments and lead on to other errors. I have 

 given with much pleasure a true detail of the fact to theillustriousM.de 

 Humboldt, who wrote me on the subject with that ardent zeal whicli cha- 

 racterizes him, and which has rendered him, as he is proclaimed in both 

 hemispheres, one of the greatest observers of nature. With respect to the 

 nature of these volcanic ashes, although I am convinced that it differs not 

 at all from that which has always been ejected, yet I wished to consult the 

 oracle of chemistry upon it, since it is his delight to discover the composi- 

 tion of bodies; I mean the illustrious Vauquelin, whose kind regard to me 

 has conferred on me so much honour. My first packet, much to my regret 

 and that of the eminent chemist who was expecting it, never reached its 

 destiny; but I renewed it, and the results shall have place in my continu- 

 ation of the History of yEtna from 1818, where I left it, which I shall soon 

 publish. I will add, to finish this note, that the "muddy eruptions" so called 

 liy our Macalubbi, are not such, even according to the imaginary ideas of 

 Plato, who admitted rivers of nmd in the interior of the globe, to which 

 end he idleged such eruptions in Sicily. Nothing comes up from the 

 depth of the earth but streams of carburetted hydrogen gas, which finding 

 above the argillaceous chalk of which the soil is formed, loosened away 

 by rain-water, it forces it up and causes it to flow in nmddy streams. In 

 times of drought, dust only is forced up, and in its passage a whistling is 

 made like an impetuous wind. Even of our lake of ihePalici they believe 

 that the water comes from the interior of the earth, and wonder that it 

 never overflows. Why do they not observe that in dry years it entirely 

 evaporates, and that nothing comes out of the chinks at its bottom but 

 currents of air, which give to the water the appearance of boiling when it 

 collects there from the rain. 



I'or 



