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 ...

An Advertisement.

First, for the better understanding and brevity sake, there are ten things to be na∣med and described, as followeth; 1. the head leg, in which the brass Revet is fixed, and about which the other turn; 2. the moveable leg, on which the Months and Days must always be; 3. the Cross piece, that is fitted to the head, and moveable Leg, by the two Tennons at the end; 4. the quadrant side where the degrees and Moneths are, for observation. 5. the other or Sector side for operation, 6thly the head center, being Center to the degrees on the inside of the crosse peece, for a forward observation as with the forestaffe. 7 The other Center, near the end of the head leg, being the Center to the moveable leg, for backward observations, (as the Davis qua∣drant is used, and the bow) which you may call the foot center, or leg center for back∣ward observations.

8thly the sights, as first the turning or eye sight, which is alwayes, set on one of the centers, with a screw to make it fast there, which I call the turning sight, 9thly the Horizon sight that cuts the degrees of altitude, and sometimes is next to the eye, and sometimes remote from the eye, yet called the horizon (slideing) sight, 10thly. the object or shaddow sight of which there may be 3 for convenience sake, as two fixed

and one moveable to slide as the horizon sight doth: the other two do serve also to pin the crosse peece, and the two legs to∣gether, through the two tennons, all whose names in short take thus:

1. The head leg: 2. the moveable leg: 3. the crosse peece: 4. the quadrant side: 5. the sector side, 6. the head (or forward) center. 7 the leg (or backward) center. 8. the turning sight. 9. the (slideing) horzon sight. 10. the object (or shaddow) sight. of which there be 3. all differing according to your use and occasions: one to slide to any place, the other 2. to be put into certain holes. nigher, or further off: as will afterwards largely appear.