text: Krishnan started the experiment in the beginning of January 1928. On 7 January, he discovered that no matter what kind of pure liquid he used, it always produced polarised fluorescence within the visible spectrum of light. As Raman saw the result, he was astonished why he never observed such phenomenon all those years. That night he and Krishnan named the new phenomenon as "modified scattering" with reference to the Compton effect as an unmodified scattering. On 16 February, they sent a manuscript to Nature titled "A new type of secondary radiation", which was published on 31 March.
  On 28 February 1928, they obtained spectra of the modified scattering separate from the incident light. Due to difficulty in measuring the wavelengths of light, they had been relying on visual observation of the colour produced from sunlight through prism. Raman had invented a type of spectrograph for detecting and measuring electromagnetic waves. Referring to the invention, Raman later remarked, "When I got my Nobel Prize, I had spent hardly 200 rupees on my equipment," although it was obvious that his total expenditure for the entire experiment was much more than that. From that moment they could employ the instrument using monochromatic light from a mercury arc lamp which penetrated transparent material and was allowed to fall on a spectrograph to record its spectrum. The lines of scattering could now be measured and photographed.