The description and use of a new sea quadrant, for Taking the Altitude of the Sun from the visible Horizon; Which is so contrived, That the Observer will be liable to no Interruption, or Inaccuracy from the Ship's Motion. And The Latitude at Sea, May be obtained with greater Certainty, and more frequently than by any Instrument of the like Kind hitherto made publick. Invented, Made, and Sold by George Adams, Mathematical Instrument Maker to His Majesty's Office of Ordnance, at Tycho Brahe's Head, the Corner of Racquet Court, in Fleetstreet, London. To which is added, The Description and Use of two Curious Methods for procuring an Artificial Horizon at Sea, To be used with Hadley's Quadrant; one by means of a Whirling Speculum; the other by a Floating Mirrour.

Date:

MDCCXLVIII. [1748]