The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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The industrial micrometer traces its origin to an astronomical micrometer invented by William Gascoigne (1612-1644) in 1639. Gascoigne's invention was designed specifically for use with telescopes and consisted of a screw-adjusting device which enabled the approximate measurement of celestial bodies. Greek theoretician Archimedes may have been the first to propose such a device in theory.
Following Gascoigne's lead, Scottish industrialist James Watt developed a pocket micrometer for his personal use in 1772. The true pioneer in micrometer design, however, was Henry Maudslay, also known for perfecting the screw-cutting lathe. Around 1805 Maudslay successfully tested a bench micrometer, which he named the Lord Chancellor. The Lord Chancellor featured a gunmetal bed, one movable and one stationary anvil, an adjusting screw with 100 threads per inch, and a graduated scale. It boasted precise measurements to within 0.0001 inch.
Since Maudslay's time, micrometers have been developed to increasingly exacting standards. In 1835 British engineer Joseph Whitworth developed a comparator to ensure uniformity of yard lengths; the device was accurate to 0.000001 inch. One of the most recent developments in micrometers--which have come to mean all devices capable of precise measurement in small units--is a hand-held micrometer that measures electronically, through diffraction grating. This device was first introduced in 1973.