Natural History. 4(77 



works, but these are arranged so badly, that the lower strata are 

 almost inaccessible. As the quartz contains no fissures or cavities, 

 no specimens of crystallized sulphur have been found. 



The sulphur does not form, as might perhaps have been sup- 

 posed, a mass or collection of veins, but is disseminated in small 

 masses, having no continuity with each other, in the quartz which 

 traverses the mica slate parallel to its strata. The apertures, by 

 which perhaps they have been united, are no longer visible ; but all 

 the quartz has suffered a singular change. It is dull, frequently 

 friable, and breaks in some places with the slightest blow, which 

 indicates splits or cracks, which are inappreciable to the sight. 

 The temperature of the rock does not differ from that of the atmo- 

 sphere. The inhabitants arc in the habit of attributing the earth- 

 quakes to which their country has been exposed, to the concavities 

 which they suppose to exist beneath the sulphur mountain. In the 

 great catastrophe of the 4th of February 1797, which destroyed so 

 many thousand Indians in the province of Quito, the three places 

 where there is most sulphur, the Cerro Quello, the Azufral de Cue- 

 saca near the town of Sbarra, and the Machay of St. Simon, near the 

 volcano of Antifana were only slightly agitated; but at a previous 

 period, an explosion resembling that of a mine occurred in the bed 

 of quartz itself, which contains the sulphur near Ticsan. — Ami. de 

 Chim. xxvii. 131. 



3. Volcanic Saline flatter. — An enormous mass of saline matter 

 was thrown out of Vesuvius during the eruption of 1822. It was 

 to the eye a mixture of two substances; the one white crystalUne, 

 lamellar and friable ; the other a hard brown red substance, con- 

 taining evidently oxide of iron. The white substance, separated 

 mechanically, was principally muriate of soda and potash mixed 

 with a little sulphate of lime. A fair sample of the whole mass, 

 when analyzed by M. Laugier, gave 



e 1 1 1 • 11 f Muriate of soda . . . 62.9 



Soluble m cold Jui- j^ ..u ir^r 



. ^ < Muriate ot potash . . 10.5 



"' ( Sulphate of lime . . . 0.5 



Soluble in hot 5 Ditto 0.6 



water, t Sulphate of soda ... 1.2 



{Silica 11.5 



Oxide of iron .... 4.3 



A hi mine 3.5 



Lime 1.3 



Water and loss ... 3.7 



100.0 



The quantity of salt present, induced many of the poor people of 

 Naples and tlie neighbourhood to store ii[) portions of the mass 

 for their domestic uses. — Aim. de Chim. xxvi. 37 J. 



