128 THE CHEMISTRY OF CREATION. 



other gases. When volcanic fires are dying out, 

 large emissions of it take place. When Vesu- 

 vius has ceased to emit lava, there escape im- 

 mense volumes of carbonic acid from the crater, 

 and these entering the atmosphere are well 

 known by the Italian people under the title of 

 the Moffettes. These streams of gas are some- 

 times dangerous to life, if a person is exposed 

 to their full influence. So largely does carbonic 

 acid escape from the ground in the far-famed 

 Grotto del Cane, near Naples, as to cause it to 

 be fatal to animals which, by accident or design, 

 axe exposed sufficiently long to its effects. All 

 the dogs for miles around dread the spot, for it is 

 a common experiment to put them into the cave 

 until they are insensible, and then to bring them 

 to life again by throwing them into a pool of 

 water. The celebrated Upas valleys owe their 

 deadly reputation to a similar cause. These val- 

 leys are described as about half a mile in circum- 

 ference, full of the skeletons of men and animals, 

 and teeming with sources of carbonic acid. They 

 are narrow, flat, and desolate the very valleys 

 of the shadow of death ; for there universal 

 death holds its reign. Heaps of dead insects 

 and ^ birds lie around, sad proofs of the deadly 

 nature of the gas.* The fatal air rises to the 



* Although there has been much fable about the Upas Valleys, 

 the deadly effects of which were attributed to the poisonous 



