Page:Reflections upon ancient and modern learning (IA b3032449x).pdf/289

 former may be very nearly adjusted, since the Application of Telescopes to Astronomical Uses has enabled Men to make much nicer Observations of the Moon's Eclipses than could formerly be made; besides those of Jupiter's Satellites, to which the Ancients were entirely Strangers. This makes our Maps wonderfully exact; which are not only the Divertisements of the Curious, but of unspeakable Use in Civil Life, at Sea especially; where, by the help of Sea-Charts, Sailers know where they are, what Rocks lie near them, what Sands they must avoid; and can as perfectly tell which Way they must steer to any Port of the Universe, as a Traveller can, upon Salisbury-Plain, or New-Market-Heath, which Way he must ride to a great Town, which he knows before-hand is not far from the Edge of the Plain, or of the Heath. Velserus has printed some ancient Maps (f), that were made for the Direction of the Roman Quarter-Masters; and if a Man will compare them with Sansons, or Blaeus, he will see the difference; which in future Ages will certainly be vastly greater, if those Countries which are now barbarous, or undiscovered, should ever come into the Hands of a Civilized or Learned People. But I have not yet done with the Load-stone.