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THE ROYAL SOCIETY OF CANADA 



is a well-defined face between è(OÏO) and z(130), and inclined at nearly 

 two degrees to the latter. This is lettered E in the figure, and has the 

 symbol (4- 13-0). The calculated angle z:E is 1° 57^', and measure- 

 ment gave 1° 42' and 1° 57'. The form i?(391), truncating the edge 

 between z(130) and c(OOl), is also present as faces of appreciable 

 width which give fair reflections. The measured and calculated 

 angles are as follows: — 



'"^ " 1 .-o Qy, calculated 10° 22' 



05' " 69° 49' 



^^R measured 10° 



:li? " 70"^ 



Figure 5. 



Two other new forms, Q{Z2\) and 5(231) appear as very narrow 

 facets truncating the edges x(lOÎ): MCJÎO) and x (10Î): z (130) 

 respectively. The angles for these faces are: 



M 

 b 



y 



Q measured 19° 52' calculated 20° 29' 



S " 45° 50' " 45° 30' 



5 " 41° 53' " 42° 10' 



Owing to the small size of the faces, the readings for these two 

 forms were obtained by maximum illumination only, but the angles 

 agree fairly closely with the calculated values. Moreover, as shown 

 in the spherical projection (figure 5), the face 5 was found to lie 

 accurately in the two zones [bSy] and [z^.t], and the face Q is similarly 



