Such, then, was the state of astronomical theories in the latter part of the sixteenth century. Enlightened men like Copernicus had guessed--not accurately, it is true, but with a considerable approach to accuracy--at the real facts of the case. Tycho Brahé (who, I suspect, would have been converted to Copernicanism if his life had been prolonged) had suggested a system of compromise not likely, in the long run, to satisfy any thoughtful mind; while the bulk of men, even the learned, adhered to the old Ptolemaic scheme. Something, however, now occurred which was destined to work, sooner or later, a complete revolution in astronomy. The telescope was invented, and, at the same time, there arose a man who knew how to use it: that man was Galileo. He was not the inventor of it, for it was first constructed in Holland or Belgium; yet he had the energy and the skill to make a telescope, without having previously seen one, simply from the account he had heard of the instrument. The telescope that he constructed, which still bears his name, was the simplest possible. It was of a form now disused excepting for opera-glasses and for the far more powerful binocular field-glasses with which we are so familiar; but for telescopes properly so called an improved principle has long since been introduced. Galileo was the first man that ever, so far as we know, turned the telescope upon the heavens. How he was rewarded for his pains we shall presently see; and I propose to introduce a narrative of the principal events in his life, since there are no means for forming a judgment so valuable as having the facts of the case clearly before the mind.
For most of the facts I am indebted to M. Henri de l’Épinois, whose elaborate article in the French publication known as _La Revue des Questions Historiques_ is of the highest value; as the author of this article has done what I suspect very few writers on Galileo have even attempted to do, namely, to inspect the documents preserved in the Vatican bearing on the process, some of which he gives at full length. Not having myself had the same advantage, I yet feel that I am treading on safe ground when I take my facts from M. de l’Épinois; for there is scarcely a statement that he makes for which he does not give his authority, whether from the documents just mentioned, or from Galileo’s own letters, or from other trustworthy evidence.[2]