Published in Spring 1996 Zeiss Historica Journal
Author: Nicholas Grossman
See Pages 6 – 7.
Carl Zeiss Jena was always involved with precision measurement and one of their products was a set of Johanneson Gauge Blocks which were “a set of blocks ground to an accuracy of one hundred-thousandth of an inch or better. These solid metal blocks were a crucial tool in the first half of the 20th century in creating the standard for a product of a precise size.
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