182 ANNUAL OF SCIENTIFIC DISCOVERY. 



progress of the oxidation could be readily followed by the change 

 of color of the surface. The experiment was tried several times 

 in an atmosphere strongly charged with the vapor tff pure car- 

 bolic acid and of cresylic acid ;* comparative experiments being 

 made at the same time in pure air. No difference in the rate or 

 amount of oxidation could be detected. 



"II. A colorless solution of subchloride of copper in ammonia 

 was prepared and divided into two parts ; one being mixed with 

 a little carbolic acid. On pouring them through the air into flat 

 white dishes, no difference in the progress of the oxidation could 

 be detected. 



" III. A mixture of pyrogallic acid and solution of potash was 

 shaken up in a large stoppered bottle. It was then opened under 

 water, and the amount of absorption of the atmospheric oxygen 

 noted. The same experiment was repeated after the addition of 

 carbolic acid to the potash solution. The same quantities were 

 used and the agitation continued for the same time. On again 

 opening the bottle under water the absorption was found to be 

 the same as before. 



"IV. The last experiment was repeated, substituting crystals 

 of sulphate of iron for pyrogallic acid. The result showed equally 

 that the presence of carbolic acid exerted no retarding influence 

 on the oxidation. 



"V. Iron filings were shaken up in water with the same re- 

 sult. 



"VI. A 'philosophical lamp' was made by arranging a pla- 

 tinum 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 

 acid were then carefully placed in the cup of the brass wick- 

 holder, surrounding, but not in contact with, the wick. The heat 

 soon melted the acid and raised its vapor round the platinum 

 spiral, but without occasioning any alteration in the brightness of 

 its glow. 



" VII. Lead pyrophorus was poured into two long and narrow 

 jars of air, one of which had its interior moistened with liquid car- 

 bolic acid. Not the slightest appreciable difference could be de- 

 tected between the rapidity of oxidation in the two jars. 



" VIII. Paper moistened with sulphate of manganese solution, 

 and dried, was dipped into caustic ammonia, both with and with- 

 out carbolic acid. No difference whatever could be detected in 

 the rate of its darkening. 



" These experiments prove conclusively that the tar acids have 

 no special power of retarding oxidation. 



"Other experiments were then instituted in the endeavor to 

 understand more clearly the mode of action of carbolic acid: 



" IX. Some meat was hung up in the air till the odor of putre- 

 faction was strong. It was then divided into two pieces ; one was 

 soaked for half an hour in chloride of lime solution, and was then 

 washed and hung up again ; the offensive smell had entirely gone. 

 The other piece of meat was soaked in a solution of carbolic acid 

 containing 1 per cent, of the acid ; it was then dried and hung up. 



