The triangular quadrant, or, The quadrant on a sector being a general instrument for land or sea observations : performing all the uses of the ordinary sea instruments, as Davis quadrant, forestaff, crosstaff, bow, with more ease, profitableness, and conveniency, and as much exactness as any or all of them : moreover, it may be made a particular and a general quadrant for all latitudes, and have the sector lines also : to which is added a rectifying table to find the suns true declination to a minute or two, any day or hour of the 4 years : whereby to find the latitude of a place by meridian, or any two other altitudes of the sun or stars / first thus contrived and made by John Brown ...

V. But if the sun be near to the Zenith or 90 degrees high, then it will be conve∣nient to move the object sight, to a hole or two further as suppose at 10, 20, 30 degrees more, toward the further end of the crosse peece and then observe as you did before in all respects, as with a Davis quadrant, and then whatsoever degrees the horizon sight cuts, you must ad so much to it, as you set the object sight forwards, as suppose 30, and

the horizon sight stay at 60, then I say 60, and 30, makes 90: the true altitude required. Note that by this contrivance, let the altitude be what it will, you shall al∣wayes have a most steady observation: with the instrument leaning against your brest, a considerable thing, in a windy day, when you may have a need of an observation in southern voyages, when the sun is near to the zenith at a Meridian observa∣tion.