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 interrup-tion, or Inaccuracy from the Ship's Motion : And the Latitude at Sea, [...] Invented, Made, and Sold by George Adams, [...] 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
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