Atomic_Clock-Louis_Essen.jpg

Summary

Description Atomic Clock-Louis Essen.jpg	English: Louis Essen and J. V. L. Parry standing next to the world's first caesium atomic clock , developed at the UK National Physical Laboratory in 1955. Deutsch: Louis Essen und J. V. L. Parry zeigen die erste Caesium-Atomuhr (1955)
Date	1955
Source	http://www.npl.co.uk/upload/img/essen-experiment_1.jpg
Author	National Physical Laboratory

This work created by the United Kingdom Government is in the public domain .

This is because it is one of the following :

It is a photograph taken prior to 1 June 1957; or
It was published prior to 1974; or
It is an artistic work other than a photograph or engraving (e.g. a painting) which was created prior to 1974.

HMSO has declared that the expiry of Crown Copyrights applies worldwide (ref: HMSO Email Reply )
More information .

See also Copyright and Crown copyright artistic works .