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ABSORPTION SPECTRA AND CHEMICAL CONSTITUTION, 353 
Hydroquinone, C,H,(OH),. 1:4, 
‘110 gram in 20 c.e. alcohol. 
With 5 mm. the spectrum is continuous to1/ 3151. With 4, 3, 2, 
and 1 mm. an absorption band appears from !/\ 3151 to 3890, 
‘110 gram in 100 c.c. alcohol. 
With 5, 4, 3,2, and 1 mm. an absorption band appears from !/A 8187 
to 3832, which gets narrower as the thickness of the layer of liquid is 
diminished. 
‘110 gram in 500 ¢.c. alcohol. 
With 5, 4, 3, and 2 mm. an absorption band appears from 1/\ 3297 
to 3531, which gets narrower as the thickness of the layer of liquid is 
reduced. With | mm. the absorption band disappears, and the spectrum 
extends to1/A 4660. 
Salicylic Acid, C,H,(OH)COOH. 1: 2. 
(From Oil of Wintergreen.) 
‘138 gram in 20 c.c. alcohol. 
With 5, 4, and 3 mm. the spectrum extends to 1/A 2986. With 
2 and 1 mm. an absorption band appears from '/A 3008°5 to 3826. 
138 gram in 100 c.c. alcohol. 
With 5, 4, 3, 2, and 1 mm. an absorption band appears from 1/2 
3008°5 to 3757, which gets narrower as the thickness of the layer of 
liquid is reduced. 
138 gram in 500 c.e. alcohol. 
With 5 mm. the absorption band appears from !/A 3080 to 3525, and 
with 4mm. from +/\ 3151 to 3494. With 3 mm. the absorption band 
has disappeared, and the spectrum extends to!/A 4033. With 1 mm. 
an absorption band appears from !/\ 4130 to 4326. 
138 gram in 2,500 c.c. alcohol. 
With 5 and 4mm. an absorption band appears from 1/\ 4130 to 
4326. With 3 mm. the absorption band has disappeared, and the spec- 
trum extends to !/\ 4550, 
Metahydroaybenzoic Acid, C,H,(OH)COOH. 1:38, 
‘138 gram dissolved in 20 c.c. alcohol. 
With 5, 4, 3, and 2 mm. the spectrum extends to 1/A 3080. With 
1 mm. an absorption band appears for 1/A 3080 to 3826. 
‘138 gram in 100 c.c. alcohol. 
With 5, 4, 3, 2, and 1 mm. an absorption band appears from !/X 3080 
to 3826, which gets narrower as the thickness of the layer of liquid is 
reduced. 
‘138 gram in 500 c.c. alcohol. 
With 5, 4, and 8 mm. an absorption band appears from 1!/\ 3187 to 
3568, which gets narrower as the thickness of the layer of liquid is 
reduced. 
With 2 mm. the absorption band has disappeared, and the spectrum 
extends to '/A 4028. With 1 mm. an absorption band appears from 
1/ 4055 to 4311. 
138 gram in 2,500 e.c. alcohol. 
With 5, 4, 3, and 2 mm. an absorption band appears from !/d 4055 
to 4311. With 1 mm. the absorption band disappears, and the spectrum 
extends to !/A 4658. 
1899, AA 
