2 matching record(s)
file W (Stack)Essen, L.
"The Quartz Clock"
in Occasional Notes of the Royal Astronomical Society, no. I, June 1938, pp. 7-12. (Account of a talk given to the Society, April 8, 1938).
[Unknown]
1938
file W (Stack)Essen, L.
"The Atomic Clock: A New Instrument for the Accurate Measurement of Time"
photocopy from Newnes Practical Mechanics, June 1949, pp. 276-278 and front cover.
[1991-8]
1949