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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1779-1855
English bricklayer and inventor who patented Portland Cement. Concrete, a mixture of cement, gravel, and sand, had existed since the time of the Romans. However, the cement portion was often of uneven quality. Aspdin discovered that the key to making hydraulic cement (cement that would harden when mixed with water) was roasting a mixture of clay and limestone powder in a furnace. Mixing this cement with sand, gravel, and water allowed the lime and clay to form a kind of gel that coated the sand and gravel, cementing them together when it dried. The hardened mixture reminded Aspdin of the prized building rock quarried on the Isle of Portland, thus the term "Portland Cement." Modern concrete contains only about 11 percent cement by weight, sand and gravel constituting over 65 percent of the weight and water most of the rest.