CII. Besides, there is another circumstance, which perhaps as yet, has never been attended to, which is, that other faculties which are seemingly very foreign from history, often serve to throw lights on various occurrences. What faculty, for example, to appearance, can have less relation to history than astronomy? but Quintus Curtius, through his gross ignorance of this science, fell into an historical error. He says, that when Alexander was marching to India, his soldiers complained loudly, that he was leading them to a country where they should not be able to see the sun. They might have had reason for this complaint, if he had been marching them Northward, in consequence of which, they would have perceived the sun to get lower, and the days to shorten upon them; but by marching towards the South, as they then were marching, they must observe the sun to get higher, and consequently, that fear in the soldiers could not have been possible. CIII. Who would think of supposing, that optics and catoptrics, and we may say the same of other mathematical subjects, could be of use in writing a history? But please to observe, that by understanding optics, you would know, what Valerius Maximus, and other authors, tell us of a man named Strabo, who, from the promontory of Lilibyum, saw and counted the ships that had just sailed out of the port of Carthage was impossible, because the image of every ship, which at such a distance, could be formed on the retina, must be so exceedingly minute as to have been imperceptible. Also by understanding catoptrics, would be known either the impossibility, or almost insurmountable difficulty of making the burning glasses, with which we are told Archimedes, at the siege of Syracuse, set fire to the ships of Marcellus; that is, if we suppose the ships to have been as far distant from the walls as some authors have placed them, which was more than thirty geometrical paces. CIV. Finally, and to sum up the whole, as human events which are the object of history, may bear analogy to the objects of all sorts of faculties, there is not one of them, which by an historian’s being acquainted with may not afford assistance in the discovery of the truth of some facts. SECT. XLIV.