472 PROFESSOlf HENRY A. MIERS ; AN ENQUIRY INTO 
If figs. 5 and G represent two adjacent octahedron faces, they will appear to be 
single planes, and may give only single visilde reflections, hut they will not be 
inclined to each other at the theoretical angle of tlie regular octahedron. This ^^ill 
doubtless explain the deviations observed by Brauns and others. The octahedron 
angle of the second crystal, described on p. 470, would appear to possess various values 
rano-ino’ between 70° 14' and 70° 39', according to the time when the crystal was 
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Fig. 9. 
taken out of the solution if it were measured in the ordinary way, and these are 
angles of precisely the sort observed by Brauns. 
When more than three images were yielded by an apparent octahedron fiice, they 
were found to be due to the fact that there were two or more triakis-octahedra; 
