Nine geometricall exercises, for young sea-men and others that are studious in mathematicall practices: containing IX particular treatises, whose contents follow in the next pages. All which exercises are geometrically performed, by a line of chords and equal parts, by waies not usually known or practised. Unto which the analogies or proportions are added, whereby they may be applied to the chiliads of logarithms, and canons of artificiall sines and tangents. By William Leybourn, philomath.

Ʋpon the Chart.

LET A represent the Place in the Latitude of 50 degr. and C that in 55 degr. whose Distance from A to C is 6 degr. Take 6 degr. out of the Meridian-line, by setting one foot as much below the lesser Latitude as above the grea∣ter, which will be from K in the Latitude of 49 ½ degr. to L in the Latitude of 55 ½; either of which are half a Degree above and under the two given Latitudes. Take this Distance K L in your Compasses, and setting one foot in A, (the lesser Latitude) with the other cross the Parallel of the greater La∣titude 55 degr. in the Point C, and draw a right Line from A to C. So shall the quantity of the Angle B A C, being found (either by your Chord or Quadrant,) shew you the Inclina∣tion of the Rhumb to the Meridian to be 33 degr. 45 min. the N. E. by N. Point.

Note, That in the Propositions following, the Difference of Lon∣gitude must always be taken out of the Aequator, and measured

thereupon also. But the Difference of Longitude and Distance upon the Rhumb must alwaies be measured upon, and taken out of, the Meridian Line of your Chart. And hereafter I shall call them the proper Difference, and proper Distance.