METHYL SALICYLATE III. 87 
TABLE I].—Methyl salicylate in the sunlight. 
Tube Date of final 
No. Date sealed. Reaeainations Contents of tube. Remarks. 
Methyl salicylate 10 ce -_________- 
1A | Mar. 9, 1911 | Sept., 1911 CEE eh Oana 
Yellow. 
Methyl salicylate 10 ce __________- 
Cha nce GS) cnscess seanel® cons zay Wacuumiss2e be Soke Se eee 
Colorless. 
Methy! salicylate 10 ce ___________ 
Ae ee ol ee ea Tasha mir bsca eed pease ng are teeta Aqueous layer colorless. 
Ester layer light yellow. 
Methyl salicylate 2 ec ____________ 
Aqueous layer colorless. 
eee dope eel water siccme re met cee ae eee y 
Ester layer yellow. 
Methy] salicylate 2 ce _.__________ 
pA | eee oy sae sale hes dovessse== Waater:Biees S27 sue nae. ee cee Colorless. 
In addition to the tubes tabulated above, more than 50 others containing 
methyl salicylate with water, sulphuric acid, atmospheric air, and other 
substances were kept in the sunlight for periods varying from a few days 
to over a year. A number of these were tested for formaldehyde with 
positive results. When hydrolysis had proceded sufficiently, amounts as 
high as 1 part in 5,000 were found, the largest amounts being in the tubes 
containing i sulphuric acid. 
From the examination of these tubes (Tables I and II), the 
following conclusions are drawn: 
In every case where oxygen was present, the methyl salicylate 
layer became colored in a short time. On bright days, the time 
required to produce a light yellow tinge was less than one hour. 
This color gradually deepened, the final color in some cases being 
a red brown. The depth of color is dependent upon the amount 
of oxygen available and the duration of the exposure. In the 
tubes containing no oxygen, namely, those with vacuum or hydro- 
gen gas, no color was visible after several weeks of exposure 
to.a bright sun during the dry season when the sun is at its 
maximum intensity. However, at the time of the final observa- 
tion on August 31, 1911, a very faint yellow tinge was visible 
in tubes containing no acid, which we believe to be due to im- 
purities absorbed from the glass. Faint traces of iron com- 
pounds will color methyl! salicylate instantly. 
