Of Objects.

THere are three Imperfections in Sight, as, the Dimness of Age or Weakness, Purblind, and Squint; Age makes all things look misty, as if there were a Veil before their Eyes; and Purblind makes all things look level, or plain, without the distinction of Parts; a Squint makes all things look double: But to look perfect and clear, is, that the two Eyes make a Tri∣angular Point upon the Object; or else the Eyes are like Burning-Glasses, which draw all the Lines of Objects to a Point, making themselves the Center.