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Rh Professors, monks, and friars were as bitter revilers of Galileo as they had been of Roger Bacon. The sleep of ages of ignorance was so rudely broken by the magical little tube he put together, that, as they rubbed their eyes and saw the old world of thought dissolving out of view, they cursed the disturber of their graveyard peace.

Galileo's first telescope magnified three diameters or nine times: his last magnified thirty-three diameters. He could not go farther with the glass lenses then in use. At thirty-eight diameters the colours, developed in the passage of rays of light through glass, or by what is called refraction, put an effectual stop to progress. Newton began where Galileo stopped. He analysed a beam of sunlight into its component colours as they are seen in the rainbow, or through a glass prism. He came to the conclusion that "refraction could not be produced without colour." He was mistaken, and the mistake of a man so eminent led the whole world astray. Acting on this belief, he argued that "no improvement could be expected from the refracting telescope," that is, from an instrument with a glass or lens at the object end of the tube to form an eye that collected and focused the rays of light. Colour, though thus barring the march of advancing science, really indicated the path of progress. But nearly two centuries elapsed before the lost road was regained, and the prism of glass became a more powerful factor in revealing the wonders of distant worlds than the best telescopes. However, progress was not wholly barred. Colours were not developed by the reflection of light from a polished surface. If, then, a highly polished mirror were placed in the bottom of a