T1IE ATMOSPHERE. 



dom, are constantly using and constantly consuming this 

 vital part of the atmosphere. Fishes can no better live 

 without air, or oxigeu, than animals upon land. This 

 oxigen they obtain from air, which is always contained 

 in water in sufficient quantities for their purposes. If 

 air is entirely removed from water by distilling, or the air 

 pump, fishes will live in it but little longer than land ani- 

 mals when shut from the atmosphere. Not only fishes, 

 but insects, and the humblest reptiles creeping in the 

 dust, need a portion of oxigen, which they are constantly 

 consuming. 



If any animal be confined in a vessel or tight room, 

 from which the atmosphere is entirely excluded, he may 

 live until the oxigen is so far consumed as to be unfit for 

 respiration, when he will die. Many persons have lost 

 their lives from the want of a supply of this vital air. 

 The most remarkable instance, of such a disaster on rec- 

 ord, occurred at Calcutta, in a prison called the ' black 

 hole.' One hundred and fortysix English prisoners were 

 forced into a room eighteen feet square, from which fresh 

 air was almost wholly excluded. Very soon after they 

 entered, a profuse perspiration commenced, followed by 

 a high fever and raging delirium, with cries, ' air, air, 

 water, water,' throwing out insults to their merciless cap- 

 tors, that they might be provoked to put them out of their 

 wretched existence. 



They entered this prison of death at eight o'clock in 

 the evening, and at six in the morning, but twentythree 

 from the whole number retained the vestiges of life. 



Although oxigen is essential to the support of life, 

 in a pure state it will soon destroy it, by the sudden and 

 powerful excitement it produces in the system. A few in- 

 halations of pure oxigen will increase the pulse from sev- 

 enty or eighty, to one hundred and twenty, or one hun- 

 dred and thirty, beats a minute. 



Inhaling air with a very little more than the common 

 proportion of oxigen, produces a sudden and remarkable 

 eflect on the system. The substance known by the 

 aame of exhilarating gas, which has a similar eflect upon 

 the feelings with ardent spirits, or more like the vapor 

 of spirits, or of ether, differs from the common atmosphere, 



