214 COSMOS. 



the Chinese province Sse-tschuan* for several thousand years, 

 and recently in the village of Fredonia in the state of New 

 York, United States, in cooking and for illumination, sulphu- 

 retted hydrogen gas and sulphurous vapours, and more rarely f 

 sulphurous and hydrochloric acids.:]; Such effusions from the 

 fissures of the earth not only occur in the districts of still 

 burning or long extinguished volcanoes, but they may likewise 

 be observed occasionally in districts where neither trachyte 

 nor any other volcanic rocks are exposed on the earth's sur- 

 face. In the chain of Quindiu I have seen sulphur deposited 

 in mica slate from warm sulphurous vapour at an elevation of 

 6832 feet above the level of the sea, whilst the same species 

 of rock, which was formerly regarded as primitive, contains, 

 in the Cerro Cuello near Tiscan, south of Quito, an immense 

 deposit of sulphur imbedded in pure quartz. 



Exhalations of carbonic acid (niofettes] are even in our days to 

 be considered as the most important of all gaseous emanations, 

 with respect to their number and the amount of their effusion. 

 We see in Germany, in the deep valleys of the Eifel, in the 



* On the Artesian fire-springs (Ho-tsing) in China, and the ancient 

 use of portable gas (in bamboo canes) in the city of Khiung-tsheu, see 

 Klaproth, in my Asie Centrale, iii. pp. 519-530. 



t Boussingault (Annales de Chimie, t. Iii. p. 181,) observed no evo- 

 lution of hydrochloric acid from the volcanoes of New Granada, while 

 Monticelli found it in enormous quantity in the eruption of Vesuvius in 

 1813. 



I [Of the gaseous compounds of sulphur, one, sulphurous acid, 

 appears to predominate chiefly in volcanoes possessing a certain degree 

 of activity ; whilst the other, sulphuretted hydrogen, has been most 

 frequently perceived amongst those in a dormant condition. The occur- 

 rence of abundant exhalations of sulphuric acid, which have been 

 hitherto noticed chiefly in extinct volcanoes, as, for instance, in a stream 

 issuing from that of Purace, between Bogota and Quito, from extinct 

 volcanoes in Java, is satisfactorily explained in a recent paper by 

 M. Dumas, Annales de Chimie, Dec. 1846. He shows that when sulphu- 

 retted hydrogen, at a temperature above 100 Fahr., and still better 

 when near 190, comes in contact with certain porous bodies, a catalytic 

 action is set up, by which water, sulphuric acid, and sulphur are pro- 

 duced. Hence probably the vast deposits of sulphur associated with 

 sulphates of lime and strontian, which are met with in the western parts 



of Sicily.] TV. 



Humboldt, Recueil d'Observ. Astronomiques, t. i. p. 311 (Nivelle* 

 ment barometrique de la Cordillcre des Andes, No. 206). 



