78 gas-jets; mud-volcanoes. 



TheYalley of Death, a deep hollow discovered 

 by modern travellers in the island of Java, pro- 

 bably owes the noxious influence, which it exerts 

 on all organic life, to carbonic acid given off 

 from the ground. 



Discharges of carbonic acid, lasting only for a 

 short time, follow regularly in the train of volcanic 

 outbursts. In the neighbourhood of Vesuvius 

 this gas is thrown up in vast quantity from crevices 

 and hollows, generally not till some weeks after 

 the outburst, and a little later cease alto- 

 gether. 



In many places carbonic acid breaks forth from 

 the earth, mixed with steam. Some of the most 

 remarkable instances of this are given by the 

 Lagoons of Tuscany; they lie in a hilly district, 

 several leagues round, in which grows no kind of 

 herb, and which is always shrouded in a white, 

 noisome mist. The ground is for the most part 

 sloping, and the soil loosened by the streams of 

 gas and vapour, which burst out from numerous 

 shifting holes. In some spots the surface is dry, 

 and often burning hot, in others it is covered with 

 muddy pools — the Lagoons. In many places one 

 finds at a little depth, a muddy mass half liquid 

 with hot water, into which the seeming hardness 

 of the surface keeps one in continual danger of 

 breaking through. The steam and gases rush up 

 with great force, partly out of clefts and openings 



