OF THE VAPOURS OF BENZENE AND ITS HOMOLOGUES. 
527 
PLATE 32. 
Fig. 1. Four spectra of benzene at a pressure of 759 • 5 mm., and at different temperatures, varying from 
12° ‘7 C. to 53° C. This series of photographs shows the head of a group of bands, being a 
narrow and somewhat feeble band, which is succeeded by a very strong band, about A 2540 at 
12°'7; it increases in strength down to 53° C. On the original plate bands are also seen about 
A 2280, A 2300, A 2330, A 2350, at 25° C., 43° C., and 53° C. For details ,see Table I., 
pp. 490-493. 
Fig. 2. Four spectra of benzene at pressures varying from 778 mm. to 21 mm., and at a constant 
temperature of 11°-5 C., see Table II., pp. 493, 494. The original plate is an exceedingly 
delicate one, very difficult to reproduce and impossible to render satisfactorily. The head of 
the group at A 2540, a narrow band, is very distinctly seen on the silver print of each of these 
spectra, but is very imperfectly shown on the reproduction. 
Fig. 6. Five spectra of toluene at different pressures and a constant temperature of 11° C. Table IX., 
p. 509. 
Fig. 7. The vapour-spectrum and solution-spectrum taken from the same quantity of benzene, and at the 
same time, for comparison. See pp. 519, 520. Bands and the heads of groups of bands are 
. indicated by marks below the two spectra. They are well seen on the original plates, although 
not all visible on the reproductions. 
