Penicillin podwer in glass tube, United States, 1943.

Monocular microscope serial No.186772

Caesium atomic clock, 1955.

Caesium atomic clock, 1955.

Caesium atomic clock, 1955.

Caesium atomic clock, 1955.

Caesium atomic clock, 1955.

Caesium atomic clock, 1955.

Testing for smog, London, 16 November 1954.

Haematology laboratory, 1981.

Haematology laboratory, 1981.

Haematology laboratory, 1981.