Natural History, 



sublimes into white and yellow crystallizations, which fusing in 

 the hotter places form nacres, ^m, and stalactites. In many parts 

 the sulphuretted hydrogen, evolved within the fumeroles, reacts on 

 the chloride, and forms sulphuret of lead, dispersed in small scales 

 through the scoria. Other fumeroles produce very thin scales of 

 the black oxide of copper ; these are very brilliant, metalloidal, 

 and flexible, and are produced by the action of the vapour of water 

 at a red heat on the chloride of copper, which may be observed 

 on disturbing the fumeroles. Here and there the reaction of 

 aqueous vapour on the perchloride of iron produces metalloidal 

 scales of the peroxide of iron ; whilst further on, the same vapour, 

 acting on mixtures of the two chlorides, produces oligiste iron in 

 small crystals, aggregated on the scoria. The muriatic acid re- 

 sulting from these actions, and the sulphuric acid which is formed 

 by the decomposition of hydrosulphurets and sulphates, attack the 

 iron, lime, copper, alumine, potash, &c., in the lavas and scoria, 

 and hence result a number of other productions which line the 

 passages of the fumeroles. 



M. Covelli descended into the crater, until within 300 feet of 

 the edge of the large eastern opening, from which the great cur- 

 rent of lava flowed in 1822. Here the fumeroles presented the most 

 beautiful crystallizations of sulphate of lime and sulphur. On 

 examining the scoria they were found incrusted and covered with 

 a substance, having all the shades of colour belonging to blue, 

 green, and black. Sometimes it resembled a spider's web in ap- 

 pearance, sometimes soot deposited in the cavities of the scoria. 

 Many specimens were collected, and also a portion of water con- 

 densed from the vapours which issued forth, and which evidently 

 contained sulphuretted hydrogen and muriatic acid. The tempera- 

 ture of the vapour was as high as 85° C, in some places, and even 

 up to 90°, at half a foot beneath the surface. 



The water being examined was found to contain only a little 

 sulphuretted hydrogen, and a little muriatic acid. The black sub- 

 stance was soon ascertained to be a pure sulphuret of copper. 

 Being analyzed, 100 parts yielded 82 parts of sulphur, and QQ of 

 copper, a loss of two parts being incurred, which accords very 

 nearly with the composition of the bi-sulphuret of copper. The 

 blue and bluish-green substances were found to be mixtures of this 

 sulphuret with sulphate and hydro-sulphuret of copper. 



M. Covelli concludes that this substance has been ibrmed by the 

 action of sulphuretted hydrogen on the sulphate and muriate of 

 copper evolved by these fumeroles ; and observes, that its compo- 

 sition accords with such an opinion, the deutoxide being that which 

 forms the Vesuvian cupreous salts. — Ann, de Chimie, xxxv. 105. 



10. Fall of the Lake Sonwando in Russia. — This lake, situated 

 in the parish of Sakkola, in the Russian government of Wibourg, 

 and surrounded by the lands of the Barons Friedrichs, was near 



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