"The Reason of the present Animadversions. ...How far Hevelius has proceeded. That his instruments do not much exceed Ticho. The bigness, Sights and Divisions, not considerably differing. Ticho not ignorant of his new way of Division. ... That so great curiosity as Hevelius strives for is needless without the use of Telescopic Sights, the power of the naked eye being limited. That no one part of an Instrument should be more perfect than another. ... That if Hevelius could have been prevail'd on by the Author to have used Telescopic Sights, his observations might have been 40 times more exact than they are. That Hevelius his Objections against Telescopic sights are of no validity; but the Sights without Telescopes cannot distinguish a less angle then half a Minute. That an Instrument of 3 foot Radius with Telescopes, will do more then one of 3 score foot Radius with common Sights, the eye being unable to distinguish. This is proved by the undiscernableness of spots in the Moon, and by an Experiment with Lines on a paper, by which a Standard is made of the power of the eye. ... A Conclusion of the Animadversions. That the learn'd World is obllig'd to Hevelius for what he hath done, but would have more, if he had used other instruments. That the Animadvertor both contrived some hundreds of Instruments, each of very great accurateness for taking Angles, Levels, &c. and a particular Arithmetical lnstrument for performing all Operations in Arithmetick, with the greatest ease, swiftness and certainty imaginable. That the Reader may be the more certain of this, the Author describes an Instrument for taking Angles in the Heavens..."