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"Sir David Gill devised a measuring machine which combines the rapidity of the glass—scale micrometer with the accuracy of the spider—line micrometer and simplifies the reductions of the observations at the same time." —Encyclopaedia Brittannica, 1910

Gill's Measuring Machine for Micrometer

"Sir David Gill devised a measuring machine which combines the rapidity of the glass—scale micrometer…