COMBUSTION IN CHLORINE. 



197 



and brought near the chlorine delivery tube mouth downwards. 

 A light is applied to the mouth of the jar, so that the hydrogen 

 takes fire ; the jar is then quickly placed over the chlorine 

 delivery tube, so that the tube projects upwards well inside the 

 jar; the jet of chlorine then takes fire and burns inside the jar, 

 combining with the hydrogen, and forming hydrochloric acid gas, 

 the action being very similar to that of oxygen when burning in 

 an atmosphere of hydrogen (Expt. 212). 



Fig. 89 shows the converse experiment; a jet of hydrogen from 

 an ordinary hydrogen generator is lighted and introduced into a 

 jar of chlorine, where it continues to burn. 



Fig. 89. Hydrogen burning in Chlorine. 



Expt. 217. Burning of a Candle in Chlorine Gas. Although 

 chlorine has a strong tendency to combine with hydrogen, as in- 

 dicated in the last experiment by the energy with which the com- 

 bination takes place, the same is not the case as regards all other 

 substances; so that when hydrogen combined with certain other 

 substances is brought into contact with chlorine, it will often 

 happen that the chlorine will combine with the hydrogen present 

 and set the other substance free, thus bringing about an action of 

 displacement (Chapter I.). This is particularly the case with 



