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.
Example.
If the object be 40 parts long, and the shaddow 80 parts, the altitude will be found to be 26. 35. But if you have the altitude, and shaddow, and would know the height of the object, then work thus:
Page 127 Take the length of the shaddow out of the line of lines, or any other equal parts, and make it a parallel tangent of 45, then take out the parallel tangent of the Suns altitude, and measure it on the line of lines, (or the same equal parts) and it shall shew the length of the object that caused the shaddow: the same rule doth serve in taking of altitudes by the rule, as in the 18 chapter, accoun∣ting the measure from the station to the object, the length of the shaddow, and the Suns altitude, the angle at the base.
