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HISTORICAL VIEW OP THE

that of modern times. The end of the fifteenth centurywas not distinguished by any great discoveries; yet itis easy to see, in the rise of a spirit of enquiry and in-vestigation, the dawn of that light which was about toilluminate Europe with so much brilliancy. The pro-gress of such improvements was, no doubt, at first slowand uncertain; but all its subsequent advance mayfairly be traced back to the original impetus given bythe philosophers of the preceding age. These, indeed,were few in number, and ill provided in their resources,yet they were carried forwards by the irresistible im-pulse of genius; they began to feel the necessity of esta-blishing the truths of science upon a firmer basis thanthe authority of Aristotle , and aspired to a higher cha-racter than that of commentators on Ptolemy .

Among those, who contributed most assiduously torearing the edifice of astronomy on the basis of observ-ation, was Bernard Walther, a rich citizen of Nurem-burg, one of the earliest and most zealous of modernastronomers. His observations, interesting on manyaccounts, are particularly remarkable for having beenmade with clocks regulated by fly-wheels, which seemto have answered tolerably well; at any rate the import-ance of such aid to the labours of the observatory wasnow generally beginning to be felt.

Walther was one of the first among the moderns whorecognised the atmospherical refraction; though he hada very incomplete notion of it, and supposed it sensibleonly near the horizon: his observations on it appear tohave been made independently of those of Vitello andAlhazen .

The capture of Constantinople by the Turks in 1452drove many Greek cultivators of science to seek a re-treat in Italy : here an asylum was afforded them, andthe libraries of that country became the depositories ofwhat remained of the treasures of Greek literature andphilosophy. It was, probably, hence that the firststimulus was given to the study of the Greek languagein Europe . Translators of the Greek authors, and com-