10 OXYGEN. 



torn, like those often used for holding sweet oil, and 

 called Florence flasks. These will bear the heat of a 

 lamp gradually applied, without breaking. Flasks of 

 this kind, made expressly for such purposes, are now 

 to be obtained in many places. When the mixture is 

 introduced, a cork with a bent tube should be fitted in, 

 and the gas collected over -yater in a cistern as before. 

 The heat requires to be continued for some time, before 

 the oxygen will begin to come off with much rapidity. 

 Having collected a sufficient quantity, the qualities 

 mentioned above will first become obvious. It will 

 then be seen, 



2. That on applying a lighted taper, the gas does 

 not inflame as did the hydrogen, nor is the taper 

 extinguished; on the contrary, it burns with greatly 

 increased and extreme brilliancy: it may be blown out 

 and relighted by immersion in this gas, so long as the 

 least particle of coal remains upon it. So intense is 

 its action as a supporter of combustion, that many 

 substances ordinarily incombustible take fire in it, and 

 burn with great splendor. A spiral roll of small iron 

 wire being tipped with sulphur, the latter lighted, and 

 then the whole plunged into this gas, the wire is 

 ignited, and burns with the utmost brilliancy. This, 

 then, is a most powerful supporter of combustion. 



3. It is no less important to the support of life, 

 whether animal or vegetable. Both plants and ani- 

 mals speedily die when introduced into any atmosphere 

 which does not contain it. In five gallons of common 

 air, there is about one gallon of oxygen : when this is 

 greatly diminished, animals die. 



If animals are brought into an atmosphere of pure 

 oxygen, the efi'ect is found to be too powerful; the 

 vital functions are so stimulated as in a very short time 

 to wear themselves out by a kind of fever, all of their 

 powers being made to act with too much energy. A 

 mouse or other small animal, placed in a jar of oxygen, 



