PASSAGE 53

　　Glass fibers have a long history. The Egyptians made coarse fibers by 1600 B.C., and fibers survive as decorations on Egyptian pottery dating back to 1375 B.C. During the Renaissance (fifteenth and sixteenth centuries A.D.), glassmakers from Venice used glass fibers to decorate the surfaces of plain glass vessels. However, glassmakers guarded their secrets so carefully that no one wrote about glass fiber production until the early seventeenth century.

　　The eighteenth century brought the invention of spun glass fibers. R é ne-Antoine de R é a French scientist, tried to make artificial feathers from glass. He made fibers by rotating a wheel through a pool of molten glass, pulling threads of glass where the hot thick liquid stuck to the wheel. His fibers were short and fragile, but he predicted that spun glass fibers as thin as spider silk would be flexible and could be woven into fabric.

　　By the start of the nineteenth century, glassmakers learned how to make longer, stronger fibers by pulling them from molten glass with a hot glass tube. Inventors wound the cooling end of the thread around a yarn reel, then turned the reel rapidly to pull more fiber from the molten glass. Wandering tradespeople began to spin glass fibers at fairs, making decorations and ornaments as novelties for collectors, but this material was of little practical use; the fibers were brittle, ragged, and no longer than ten feet, the circumference of the largest reels. By the mid-1870's, however, the best glass fibers were finer than silk and could be woven into fabrics or assembled into imitation ostrich feathers to decorate hats. Cloth of white spun glass resembled silver; fibers drawn from yellow-orange glass looked golden.

　　Glass fibers were little more than a novelty until the 1930's, when their thermal and electrical insulating properties were appreciated and methods for producing continuous filaments were developed. In the modern manufacturing process, liquid glass is fed directly from a glass-melting furnace into a bushing, a receptacle pierced with hundreds of fine nozzles, from which the liquid issues in fine streams. As they solidify, the streams of glass are gathered into a single strand and wound onto a reel.

　　1. Which of the following aspects of glass fiber does the passage mainly discuss?

　　(A) The major developments in its production

　　(B) Its relationship with pottery making

　　(C) Important inventors in its long history

　　(D) The variety of its uses in modern industry

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