s,v 



420 GEOMETRY, 



Note. And ttius any number of any kind of figurcf 

 piay be added together. 



PROBLEM L, 



To construct the lines of the Plane Scale, 



The divisions on the Plane Scale are of two kinds *, on^ 

 kind having relation merely to right lines, and the other to 

 the circle and its properties. The former are c;illed Linesy 

 or Scales^ of Equal Farts, and are either siraj)le or diagGnal, 



By the Lines of the Plane Scale we here mean the follow- 

 ing Lines, most of which commonly, and all of them 

 sometimes, are drawn on a Plane Scale. 



1. A Line or Scale of Equal Parts, marked f. P, 



2. . . • » < • Chords . . 4 . Cho. 



3 Rhumbs .... Rhu. 



4. . . . • . • Sines , . . . , Sin. 

 ^ ". tangents / * ^ . . Tan. 



6. ..... . Secants . , . . Sec. 



7. ••.... . Semiiangents . . . S. T. 

 '8 . Longitude .... Lon. 



9 Latitudes .... Lat. 



10 Hours .... Ho. 



II » . Inclination f Meridians Ll. Mer. 



