10 



OXYGEN. 



to.m, 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 water 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 w r ire 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 effect 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. 



