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.