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Detroit, Michigan. New method of making x-ray photographs size 4x5 inches instead of larger. Used at the Herman Kiefer Hospital for Communicable Diseases to show various stages of tuberculosis. The patient is placed in front of a flurescent screen and this screen is photographed on ordinary photographic film by means of a lens of larger aperture

Detroit, Michigan. New method of making x-ray photographs size 4x5 inc...

Public domain photograph of 1930s industry, war production in the United States free to use, no copyright restrictions image - Picryl description

Chrysler tank arsenal. This is a milling operation. The four-pound metal piece with the aperture is actually the turret for a 37 mm anti-aircraft gun, part of the equipment for an M-3 tank. Extreme accuracy is required in the milling of these parts, because it is important that they be able to move freely. The gun is designed for straight away shooting, as well as serial shooting. The twenty-eight ton M-3 tanks are made in Detroit, at the huge Chrysler tank arsenal

Chrysler tank arsenal. This is a milling operation. The four-pound met...

Public domain image of an industrial building, factory, structure, works, 19th-20th century industrial revolution, free to use, no copyright restrictions - Picryl description