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.
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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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1682-1744
English mathematician and inventor who built the first working reflector telescope. Hadley built his Gregorian reflector telescope in 1721. The device contained a 6-inch (15.2-cm) mirror, and proved accurate enough to be successfully used by astronomers. The response to Hadley's invention was so favorable, he later built a larger, more sophisticated version. In 1730 he invented a quadrant, known as Hadley's quadrant, which was used to measure the altitude of the Sun or a star in order to ascertain a ship's geographic position while out at sea. His design eventually evolved into a sextant, a navigational instrument that measured the distance between the horizon and either the Sun or stars.