A sea quadrant
Date
1692
Creator
Edmond Halley (1656 - 1742, British) , Astronomer
Object type
Archive reference number
Manuscript page number
p4
Material
Dimensions
height (page): 305mm
width (page): 192mm
width (page): 192mm
Subject
Content object
Description
Edmond Halley describes an instrument, a sea quadrant, that can see at once the horizon and the object 'distinctly and enlarged'.
AB is a brass pipe with the eyeglass, or lens, placed at A. CD is also a hollow pipe with a telescope lens at G.
The front page of the document describes an experiment on the running of water, as described in the Journal Book.
AB is a brass pipe with the eyeglass, or lens, placed at A. CD is also a hollow pipe with a telescope lens at G.
The front page of the document describes an experiment on the running of water, as described in the Journal Book.
Transcription
At length I present I have attaind what will with all possible realness perform the thing required: that is to make a sea quadrant wherin both the horizon and object shall both be seen dinstinctly and enlarged at one view in the common focus of a telescope.
Transcribed by the Making Visible project
Transcribed by the Making Visible project
Object history
23 March 1692, 'Halley gave an account of an Experiment lately made by one Mr Constable of Reading; viz that water did run out faster at the same hole in a Vessel of 13 1/2 Diameter, than at 22 1/2 Diameter, and this by repeated experience, the water being carefully kept at the same hight. This appeared to the Company to be occasioned by the fall of the water poured into the Vessle, which being determined downwards encreased the force of the water pressing out at the hole more in the small Vessell, than the greater' (JBO/9/78).
Associated place