USING the 2536.5 radiation of the mercury arc as the exciter and a Hilger Intermediate quartz spectrograph, the faint second-order Raman spectrum of diamond was first successfully recorded by me 1.

So far, the study of the Raman effect has been confined to the visible region of the spectrum only. By the use of an all-quartz apparatus similar to that of glass used by Prof. Wood (Phil.