Roberts Micrometer (c. 1870)

In the mechanical age, precision was essential, since carefully measured parts had to fit together in complex machines such as steam engines, automobiles, and jet aircraft. But achieving precision was not always possible because it required the preliminary development of knowledge tools that unified ideas and material culture. One such tool was the micrometer, which allowed mechanical engineers and toolmakers to read fine gradations of measurement. Shown here is a Roberts Micrometer used in Germany at the beginning of the 1870s.