S. L. Penfield — Crystal Drawing. 67 



so that the b axis runs from front to back. The list of 

 forms is not given here because, if needed, it may be found 

 in an earlier publication.* Endeavoring to preserve the 

 true proportions of the faces, it proved to be a difficult matter 

 to construct the orthographic projection II, as seen in the 

 direction of the vertical axis. An end view of the crystal, an 

 orthographic projection as seen in the direction of the b axis I, 

 was therefore first drawn, a comparatively easy task, and 

 tilting it at an angle of 18° 26', as shown in the figure, the 



orthographic projection II was readily made by projecting as 

 indicated by the arrows, and, finally, the clinographic projec- 

 tion III, in exactly the desired proportions was made. In 

 studying the forms of a complex crystal, such as represented 

 by figure 51, the orthographic projection I (end view) is 

 doubtless more satisfactory than either of the other projec- 

 tions. 



For the triclinic system three illustrations are offered. The 

 clinographic projection of axinite, figure 52, is \ery satisfac- 

 tory, but its proportions are made more real by the accom- 

 panying orthographic projection. In the examples chalcanth- 

 ite and anorthite, figures 53 and 54, the clinographic projections 

 taken alone are inadequate because of the foreshortening of 

 several of the prominent faces, but supplemented by the accom- 

 panying orthographic projections the combinations are readily 



* This Journal (4), xiv, p. 278, 1902. 



