THE EARTH. 65 



and over others the fields are found destitute of verdure.' The 

 inhabitants, also, are rendered di'eadfully sensible of these sub- 

 terraneous exhalations, being afl'ected with such a variety of evils 

 proceeding entirely from this cause, that books have been pro- 

 fessedly written upon this class of disorders. 



Nor are these vapours, \Thich thus escape to the surface of 

 the earth, entirely unconfined ; for they are frequently, in a man- 

 ner, circumscribed to a spot. The grotto Del Cane, near 

 Naples, is an instance of this ; the noxious effects of which have 

 made that cavern so ve.y famous. TLis grotto, which has so 

 much employed the attention of travellers, lies within four 

 miles of Naples, and is situated near a large lake of clear whole- 

 some water. 5 Nothing can exceed the beauty of the landscape 

 which this lake affords ; being surrounded with hills covered 

 vviih forests of the most beautiful verdure, and the whole bear- 

 ing a kind of amphitheatrical appearance. However, this region, 

 beautiful as it appears, is almost entirely uninhabited ; the few 

 peasants that necessity compels to reside there, looking quite 

 consumptive and ghastly, from the poisonous exhalations that 

 rise from the earth. The famous grotto lies on the side of a 

 hill, near which place a peasant resides, who keeps a number of 

 dogs for the purpose of showing the experiment to the curious. 

 These poor animals always seem perfectly sensible of the ap- 

 proach of a stranger, and endeavour to get out of the way. 

 However, their attempts being perceived, they are taken and 

 brought to the grotto ; the noxious effects of which they have 

 so frequently experienced. Upon entering this place, which is 

 a little cave, or hole rather, dug into the hill, about eight feet 

 high, and twelve feet long, the observer can see no \nsib!e mark 

 of its pestilential vapour ; only to about a foot from the bottom, 

 the wall seems to be tinged with a colour resembling that which 

 is given by stagnant waters. When the dog, this poor philoso- 

 phical martyr, as some have called him, is held above this mark, 

 he does not seem to feel the smallest inconvenience ; but when 

 his head is thrust dovn\ lower he struggles to get free for a 

 little ; but in the space of four or five minutes he seems to lose 

 eI! sensation, and is taken out seemingly without life. Being 

 plunged in the neighbouring lake, he quickly recovers, and 



2 Boyle, vol. iii, p. 238. ^ Klrrhrr, Muud. Subt. voL i. p 191. 



