sir c.v.raman

The molecular scattering of light
Nobel Lecture, December 11, 1930
The colour of the sea
In the history of science, we often find that the study of some natural phenomenon
has been the starting-point in the development of a new branch of
knowledge. We have an instance of this in the colour of skylight, which has
inspired numerous optical investigations, and the explanation of which, proposed
by the late Lord Rayleigh, and subsequently verified by observation,
forms the beginning of our knowledge of the subject of this lecture. Even
more striking, though not so familiar to all, is the colour exhibited by oceanic
waters. A voyage to Europe in the summer of 1921 gave me the first
opportunity of observing the wonderful blue opalescence of the Mediterranean
Sea. It seemed not unlikely that the phenomenon owed its origin to
the scattering of sunlight by the molecules of the water. To test this explanation,
it appeared desirable to ascertain the laws governing the diffusion of
light in liquids, and experiments with this object were started immediately
on my return to Calcutta in September, 1921. It soon became evident, however,
that the subject possessed a significance extending far beyond the special
purpose for which the work was undertaken, and that it offered unlimited
scope for research. It seemed indeed that the study of light-scattering might
carry one into the deepest problems of physics and chemistry, and it was this
belief which led to the subject becoming the main theme of our activities at
Calcutta from that time onwards.