DRAWING-BOARD FOR STEREOGRAPHIC PROJECTION 755 



The process of drawing is extremely simple. A sheet of tracing 

 paper is fastened to the board (A-A) by means of thumb tacks and 

 all angles and distances are measured directly by rotating the net 

 into the desired positions. Since in stereographic projections all 

 circles and angles appear in true proportions, such a drawing-board 

 should find extensive use for map drawing as well as for crystal 

 projection. 



