The description and use of a joynt-rule fitted with lines for the finding the hour of the day and azimuth of the sun, to any particular latitude, or, to apply the same generally to any latitude : together with all the uses of Gunters quadrant applyed thereunto ...
Brown, John, philomath.
PROP. 18.
To finde the Angle of 6 from 12, in erect Decliners.
As the latteral tangent of the comple∣ment
of the latitude,
To the parallel sine of the declination
of the Plain:
So is the parallel sine of 90:
To the latteral tangent of the Angle
between 12 and 6.
Page 133 Thus you see the natural Sines and Tangents on the Sector, may be used to operate any of the Canons that is performed by Logarithms, or the ar∣tificial Sines and Tangents, by chang∣ing the terms from the first to the third, and the second to the first, and the third to the second, and the fourth must always be the fourth, in both workings being the term required.
