OXYGEN. 9 



lightest of known bodies. This can be shown by 

 turning the mouth of a jar filled with it suddenly up- 

 ward, and at the same moment applying a taper. 

 There will be a slight explosion, and a body of flame 

 risino; from the jar. On the other hand, if the jar be 

 gently liftetl and the flame applied beneath, the burning 

 will be inside of the jai;, and quite gradual. This 

 property may also be shown by filling a bladder with 

 the gas, and allowing it to rise. It is often used for 

 filling balloons, its lightness giving them very great 

 buoyancy. 



4. Mixed with common air, this gas is dangerously 

 explosive. The first portions which pass over from 

 t^ ■' are therefore to be rejected; and a match 



er to ke applied to a iar or bottle containing 

 it, or in which it is l)eing made, tcithottt having first 

 tested the purity of a small quantity collecte<l in a little 

 tube. If this bums quietly when a taper is placed 

 beneath its mouth, the gas is sufficiently pure to use 

 with safety. 



5. This gas can be breathed without very injuriooB 

 effects, but it will not sustain life. In an atmasphere 

 of pure hydrogen, every animal would soon die. 



The next of these three RMO u one of exceeding 

 importance : its name is Oxyft^n. It is colorless, 

 tav!. less and ino<loroas, like hydrogen, that is, when 

 pure: as ordinarily made, it has some •••"■"ities. 

 The easit'st way of preparing it is to i me 



« ' ' tash with a small portion lack 



in*"!*". Both of tho«e suhst w be 



V MS. 



' inary experiment:i 



t:.. .. !i should be powd-ri-. .:...: ...... i- 



fore \ ith the manganese. When all is ready, 



the itiiMui IS to be put into a flask with a thin bot- 



