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ON THE ABSORPTION SPECTRA OF THE VAPOURS OF BENZENE, etc. 
PLATE 33. 
Pigs. 3 and 4. Seventeen spectra of benzene vapour at different pressures, varying from 767 mm. down to 
4*mm., at a constant temperature of 100° C., in a column 150 mm. long. These two series of 
spectra, the one in continuation of the other, show completely what was only indicated on 
fig. 2. See Table IV., p. 496, and Table VI., pp. 498-505. 
On fig. 3, the least refrangible group of bands is well shown about A 2700, at 484 mm. 
pressure, and continues to 88 mm. 
On fig. 4, the bands about A 2700 are strong at pressures from 67‘5 mm. to 28-5 mm. At 
the latter pressure the bands at A 2600 become well defined. From 67 • 5 mm. to 22 ■ 5 mm. 
the bands at A 2280, and near to A 2300 are visible. 
Fig. 5. This is a very fine series of spectra of toluene vapour at nine different temperatures from 10° C. to 
100° C., and at a constant pressure of 751 mm., in a column 150 mm. long. See Table VIII., 
pp. 507, 508. 
