Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
‘A Corner of the Institute to Ray Therapy, showing school children being treated with two mercury arcs (Jesioneks) and an incandescent filament lamp (Sollux),’ in Beaumont W (1931) Fundamental Principles of Ray Therapy: An Elementary Textbook for Nurses, Students, and Practitioners. H. K. Lewis & Co. Ltd., London, fig.3, p.6.
