RUDE ANALYSIS OF AIR. 



205 



That a definite idea may be formed of this 

 singular process, by which we learn this im- 

 portant part of the chemical constitution of 

 the air, the method of conducting the expe- 

 riment with the substance Phosphorus, may 

 be shortly stated. A portion of air should be 

 confined in a glass tube, over 

 distilled water, in which a small 

 piece of phosphorus, fixed to the 

 end of a wire, should be placed. 

 The tube should be graduated into 

 a number of divisions, by which 

 the height of the contained water 

 may be ascertained. After the 

 lapse of some hours, the water in- 

 side the vessel will be found at a 

 higher mark than before. This 

 indicates that a certain amount of 

 air, equal to the amount of increase in the 

 height of the water, has been abstracted. After 

 a time, the water ceases to rise, and then the 

 process is complete. On removing the jar and 

 putting a lighted taper into the remaining air, 

 it will be found to go out directly, and a small 

 animal would be suffocated by it. These are 

 not the characteristic effects of oxygen ; the 

 residue is therefore nitrogen, the oxygen having 

 entirely disappeared. The calculation is now 

 easy, the water indicates the amount of oxygen 



EUDIOMETER. 



