Plus ultra, or, The progress and advancement of knowledge since the days of Aristotle in an account of some of the most remarkable late improvements of practical, useful learning, to encourage philosophical endeavours : occasioned by a conference with one of the notional way / by Jos. Glanvill.

CHAP. VI. Improvements of Opticks and Geography. (Book 6)

I Come next (5.) To consider the OPTICKS, whose Improvements are of great importance in the matters of gene∣ral Philosophy and humane Life; since the

••••formations of Sense are the ground of ••oth, and this Science rectifies and helps the ••oblest of them. Concerning it, there was once a Book of Aristotle's extant, ac∣cording to Laertius: but it hath submitted to Time. Since him, this Science hath been cultivated by Euclide, and the ce∣lebrated Archimedes, who is said to have done strange things by it, upon the Ships of Marcellus: As Proclus, who impro∣ved the Archimedean Artifices, destroyed a Fleet by his Specula Vstoria, that besieged Constantinople. Ptolomy of Alexandria made considerable Improvements of Opticks; and Alhazenus the Arabian, is famous for what he did in It. From these, Vitellio drew his, and advanced the Science by his own Wit, and their Helps. Stevinus corre∣cted Euclide, Achazen, and Vitellio, in some fundamental Propositions that were mistakes; and in their room substituted considerable Inventions of his own. Roger Bacon our fam'd Countryman, whom Picus Mirandula calls the Phoenix of his Age, and Vossius, one Learned to a miracle, writ acutely of Opticks. He was accused of Magick to Pope Clement iv. and thereupon imprison∣ed: But the Accusation was founded on nothing but his skill in Mathematicks, and

the ignorance of his Accusers. After these, the Dioptricks were improved by Kepler, Gassendus, Mersennus, and the noble and incomparable Des Cartes, who hath said the most clear, useful, and improva∣ble things about it, that ever were extant on the Subject. But nothing hath so much advanc'd the Science, as the invention of the Telescope by Metius; and that other of the Microscope, concerning which I have to say in the following Instances. I pass therefore to the last I shall mention in the Mathematicks, which is,

(VI.) GEOGRAPHY. In this the Ancients were exceedingly defective. And Aristotle knew the World, by the same figure his Scholar conquer'd it. 'Tis noted by the ingenious Varenius, that the most general and necessary things in this Science were then unknown; as, The Habitableness of the torrid Zone; The flux and reflux of the Sea; The diversity of Winds; The Polar propertie of the Magnet; The true dimen∣sion of the Earth. They wanted Descripti∣ons of remote Countries, concerning which both the Greeks and Romans had very fabu∣lous Relations. They knew not that the Earth was encompassed by the Sea, and

might be Sailed round. They were totally ignorant of America, and both the North and South parts of this Hemisphere; yea, and understood very little of the remoter places of their own Asia. Iapan, the Ia∣va's the Philippicks, and Borneo, were ei∣ther not at all known, or exceeding imper∣fectly of old: But all these are familiar to the latter Times. Mexico and Peru, and the vast Regions of those mighty Empires, with the many Isles of the Great Sea are disclosed. The frozen North, the torrid Line, and formerly unknown South, are vi∣sited, and by their numerous Inhabitants found not to be so inhospitable and unkind to men, as Antiquity believed. The Earth hath been rounded by Magellan, Drake, and Candish. The great Motion of the Sea is vulgar, and its varieties inquiring every day: The diversities of Winds stated, and better understood: The Treasure of hidden Vertues in the Loadstone, found and used. The Spicy Islands of the East, as also those of the remote South and North, frequented, and the knowledge of that People and those Countries transmitted to us, with their Riches; The most distant being Parts Tra∣vell'd and Describ'd. Our Navigation is far greater, our Commerce is more general,

our Charts more exact, our Globes more accurate, our Travels more remote, our Reports more intelligent and Sincere; and consequently, our Geography far more per∣fect, than it was in the elder Times of Poly∣bius and Possidonius, yea than in those of Ptolomy, Strabo, and Pomponius Mela, who lived among the Caesars. And if It was so short in the flourishing Times of the Roman Empire, how was it before, in the days of Aristotle and the Graecians? We have an Instance of it in the Great Macedonian, who thought the bounds of his Conquests to be the end of the World; when there were Nations enough beyond them, to have eaten up the Conqueror, with his proud and trium∣phant Armies. So that here also Modern Improvements have been great; and you will think so, if you compare the Geogra∣phical Performances of Gemma Frisius, Mer∣cator, Ortelius, Stevinus, Bertius, and Guil. Blaeu, with the best Remains of the most celebrated Geographers of the more ancient Ages.