LIGHT ON LIGHT

Evening Post, Volume CXVI, Issue 31, 5 August 1933, Page 17

LIGHT ON LIGHT

SCIENCE SIMPLIFIED

Perhaps the chief significance of "The Universe of Light," by Sir William Bragg, is that it is-the first book to expound, in such a manner that the unscientific can understand it without difficulty, a conception of tho universe familiar as yet to few but physicists: a theory that in its implications may well prove as revolutionary as any that has' disturbed human complacency in tho past, for it suggests that tho whole universe is' composed of something of the nature of light; "Light," we are told early in the book, "using the full meaning of the word, transmits energy which is the mainstay of life, and gives to living beings the power of observation: and it is akin to the matter at ■MfJiich all things, anipate and inanir mate, aro made. The universe is its sphere of action. We do it no more than justice when we speak of the Universe of Light."

The reader by easy transitions' is made familiar with the idea of invisible light and o£ "colours" which he can neither, see nor imagine. He learns that tho light we behold.with our eyes is but one "octave" out of a long scale of some sixty octaves of ether wave-lengths already exploitable by tha methods of physics—a gamut reaching from great radio.waves at one end to the inconceivably minute waves of Xrays, and perhaps including cosmic rays bombarding our planet from outer space, at tho other end. The chapters on colour are among the most interesting. They are illustrated by beautiful coloured plates, and make clear the different nature of the colours of sea and sky, soap bubble's, birds' foafchnr», flowers," artificial dyes, and so forth. .