414 



APPENDIX 



ON DRAWING THE 



The length and position of the line g e may be also 

 very easily determined geometrically. 



Make b p, fig. 375, equal to b g, fig. 374, and b n 

 equal to b e of the same figure. From b as a centre, 

 describe the semicircle n o, and the segment p g. 

 Take n e equal to the arc of 90 / 3 , and p g equal 

 to the same arc, and ge will obviously be the greater 

 diagonal of the horizontal projection of the base of 

 the prism. 



Knowing the horizontal projection g b e 7i, we 

 may proceed to the projection of the prism ; elevating 

 i i'j m m', sufficient to exhibit the terminal plane, 

 and taking k k 1 equal to a f, fig. 374, and i" i'" equal 

 to c e of the same figure. 



To draw a Rhomboid. 

 Fig. 376. 



The ratio of the axis, to a .perpendicular drawn 



