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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1597-1636
English astronomer who discovered secular variations in magnetic declination—changes over time in the acute angle between magnetic and true north. Edmund Gunter's declination measurements at Limehouse in 1622 were about 5° less than William Borough's 1580 results. Gunter attributed the discrepancy to errors by Borough. Gellibrand and John Marr's 1633 measurements showed a further decrease, which Gellibrand announced in 1635. Gellibrand also made mathematical contributions to navigation including a method for determining longitude at sea.