The results of a study of the Raman spectra of nine aldehydes and of mesitylene are reported and discussed in this paper. Of these substances, only a few, namely, paraldehyde, acetaldehyde and benzaldehyde have been previously investigated by other authors and the rest receive attention for the first time. The experimental arrangements were the same as those described by Wood. Hilger’s quartz. E
2
and a two prism glass spectrograph of high light gathering power were used for studying the spectra. The liquids were mostly Kahlbaum’s or Merck’s extra pure and were further purified by distillation in vacuum before use. Capric, undecylic, and lauric aldehydes were, however, obtained from other sources and were used as received. In the following tables are given the wave-numbers and the intensities of the Raman lines, and the shifts in wave-numbers between them and the exciting lines. In the column ∆
v
the letters
a, b, c, d, e, f, g, h, k, l
and
m
represent the exciting lines of the mercury spectrum
λ
A. U. 3650⋅1, 3654⋅8, 3663⋅3, 4046⋅6, 4077⋅8, 4339⋅2, 4347⋅5, 4358⋅3, 5460⋅7, 5769⋅5, 5790⋅5 respectively.
Wide-Field-Imaging 3-Mirror-Systems by High Light Gathering Power and a
Wide-Field Optical System for the ‘Large Imaging Telescope’ (Lite)