Notice of Active and Extinct Volcanos. 79 



from lava in the proportion of nine per cent, simply by wash- 

 ing, and the latter is sometimes so abundant as to form an 

 article of commerce. 



Sulphureous vapors are justly regarded as characteristic 

 of a true volcano, and they have been observed in Bourbon, 

 Java, the Sandwich islands, Kamschatka, &c. 



The Rio di Vinegro, or vinegar river, mentioned by Hum- 

 boldt, flows from the extinct volcano of Purace, near Popa- 

 yan. The waters are fatal to fish, and the spray irritates the 

 eyes of observers. In a litre of this water (2.1 13 pints) there 

 were found, sulphuric acid 16.68 grains, muriatic acid 2.84, 

 alumine 3.7, lime 2.47, and traces of iron. The crater emitted 

 sulphurous acid abundantly, and there was a deposit of very 

 pure sulphur, eighteen inches thick. A lake within the cra- 

 ter proved to be a saturated solution of sulphuretted hydrogen, 

 from whose reaction with the sulphurous acid, it is probable 

 the sulphur arose. 



There is a similar river in mount Idienne, in Java, of which 

 the following account is contained in Vol. 1, of this Journal, 

 page 58. Great quantities of very pure sulphur, are obtain- 

 ed in the crater of a large and now nearly extinct volcano, 

 about sixty miles from the town of Batavia. It is in the cra- 

 ter that the famous lake of sulphuric acid exists, and from 

 which it flows in a river down the mountain, and through the 

 country below. In the dry season it is absorbed by the 

 sands, but at other times, another river, called the white riv- 

 er, unites with this, some miles below its origin ; this river, 

 turbid with suspended white clay, is salutary to men and ani- 

 mals ; fishes live in it, and vegetation is nourished by its wa- 

 ters ; but, after the junction, it becomes clear ; the acid dis- 

 solves the earthy particles, which discolored it, and it now 

 becomes fatal to living beings — kills the fish, destroys the 

 vegetation, and corrodes the stones in its channel. This riv- 

 er is called Songi Pouti. Analysis, by Vauquelin, shewed, 

 that sulphuric acid was most abundant in this water; it con- 

 tained also, muriatic acid, and small portions of sulphates of 

 iron, alumine, and lime, and a little sulphur. — Tillock's Phil. 

 Mag. vol. xlii, page 182. Annales du Musee, Tome xviii, 

 page 425 ; the latter quoted by Daubeny. 



Carbonic acid gas is given out by volcanos, chiefly when 

 nearly extinct ; but, it has not been observed, when they are 

 in vigorous action. Professor Daubeny suggests, that in such 

 circumstances, it may be decomposed by potassium, and that 



