Abstract
THE SPECTRUM OP RADIATION TlHE visible spectrum is only a small portion of the complete spectrum of ethereal waves. Beyond the violet with progressively decreasing wave-lengths, come successively the radiations called ‘ultra-violet,’ soft X-rays, hard X-rays, the gamma rays of radium, and the very penetrating radiation, the so-called cosmic rays, which have only recently been proved to be of extra-terrestrial origin. Similarly, beyond the red, in progressively increasing wave-lengths, come in turn infrared and the Hertzian waves used in radio communication.
Article PDF
Rights and permissions
About this article
Cite this article
HOPWOOD, F. The Physical Basis of Light Therapy1. Nature 121, 625–630 (1928). https://doi.org/10.1038/121625a0
Issue Date:
DOI: https://doi.org/10.1038/121625a0