METHYL SALICYLATE III. 91 
Some experiments have been performed in sealed tubes in the 
same manner, with salicylic acid, which led to the belief that 
it also colors in the presence of oxygen and sunlight when dis- 
solved in xylene or alcohol. The rate of color formation is in 
every case so slow that it is not certain that the reaction is 
not entirely due to impurities, such as iron compounds, dissolved 
from the glass. 
TABLE VII.—Salicylic acid and sodium salicylate in sunlight. 
Date of final 
Date sealed. examination. 
Mixture. Remarks. 
Salicylic acid 0.1 gram__________ 
2X | Oct. 14,1908 | Aug. 3, 1909 ‘ f less. 
= ae Sulphuric acid x AN) a a CROMER 
Sodium salicylate 0.1 gram _____ 
pCi eee doyesae-- tenes (ot Pee B e 
S ° : Water 10'ce!J22225=25-=- === 4-55 roe 
Sa ae = =a | = 
| Salicylic acid 0.1 gram _________ | 
7g) ane domes. |e vdowe=2es Sulphuric acid N 10 ee-_--___--- | Chloroform light yellow. 
Chloroform 2 ce ------_--------- 
Salicylic acid dissolved in xylene also developed a yeilow 
color in the sunlight. A tube containing salicylic acid 0.1 gram 
and x sulphuric acid 10 cubic centimeters was heated for eight 
months on a steam bath in the dark to 100° with the formation 
of no color and no noticeable internal pressure. 
The three hydroxy benzoic acids ——The meta compound is 
quickly acted on by the sunlight and oxygen, the ortho quite 
slowly if at all, and the para practically not at all. 
The esters of these acids behave in the same way, but the ortho 
and meta are much more rapidly colored. 
The three cresols.—The meta compound is colored yellow in 
the presence of oxygen and sunlight in about one hour and the 
ortho and para more slowly. The ester of p-cresol remains 
colorless. 
The results obtained with these compounds in sunlight are 
given in Table VIII. 
