Vol. 62.] THE EECENT EEUPTI0N OF VESUVIUS. 483 



previously undergone the action of fumaroles, in such wise as to 

 originate the formation of minerals of metamorphic nature. Con- 

 sequently, not only do chlorides and sulphates abound, but also 

 ejectamenta of big crystals of magnesian mica, hornblende, pyroxene, 

 etc., sometimes occurring singly, and sometimes grouped together in 

 crystalline blocks such as those described by A. Scacchi from the 

 eruption of 1872, and among which the presence of sylvite is note- 

 worthy.— May 80th, 1906^ 



Discussion. 



The Chaieman (Mr. A. Steahan) remarked that it had been a 

 pleasure to hear this interesting account of the recent eruption from 

 one of the Foreign Correspondents of the Society. The British Isles 

 had been not inaptly described as a Museum of Geology, but they 

 could show no active volcano. 



Mr. W. V. Ball desired to know whether the extraordinary 

 phenomenon of the sinking of the sea-level after an eruption was a 

 frequent consequence of volcanic eruptions. He did not remember 

 hearing of any such occurrence before; but there was doubtless 

 some eminent geologist present who could enlighten him on that 

 point. 



Prof. Gaewood said that he would like to call attention to the 

 photograph and samples of dust exhibited through the kindness of 

 Mr. Arthur Collins, who was present at Naples during the eruption. 

 The dust illustrated in an interesting manner the variation in 

 character which it underwent as the eruption progressed, owing to 

 the changes which took place after the collapse of the cone, as 

 described by the Author in his paper. 



