270 DOES CARBOLIC ACID PREVENT OXIDATION ? 



oxygen, it being supposed that it acts merely by pre- 

 venting oxidation. In order to a thorough clearing 

 up of this point, Mr. Crookes made the following 

 experiment : 



Metallic sodium was cut into lumps with a sharp 

 knife : the change of colour of the surfaces indicating 

 very plainly the progress of the oxidation. The same 

 was done several times in an atmosphere strongly 

 charged with the vapour of carbolic acid, while com- 

 parative experiments were made at the same time 

 in pure air. Result no difference in the rate or 

 amount of oxidation. In a second experiment, " a 

 colourless solution p of subchloride of copper in am- 

 monia was divided into two parts, and one part mixed 

 with a little carbolic acid. On pouring the two por- 

 tions through the air into flat dishes, no difference 

 whatever on the progress of the oxidation could be 

 detected." In another, " a mixture of pyrogallic acid 

 and a solution o potash was shaken up in a large 

 stoppered bottle. It was then opened under water, 

 and the amount of oxygen noted. The same experi- 

 ment was repeated after the addition of carbolic acid. 

 On opening the bottles under water, the absorption 

 was found to be the same as before." In a fourth 

 experiment, a " ' philosophical lamp ' was made by 

 arranging a platinum spiral over the wick of a spirit 

 lamp, containing alcohol mixed with a little ether. 

 On lighting, and then blowing it out, the platinum 

 continued to glow brightly. Pieces of solid carbolic 



