352 Palache and Wood — Crystallograp/iic Study of Millerite. 



Crystal. 



Signal. 



Beading. 









i> 



1 



very poor 



16° 



48' 



2 



very poor 



17° 



30' 



2 



very poor 



17° 



33' 



3 



poor 



17° 



58' 



3 



poor 



17° 



59' 



4 



good 



17° 



47' 



4 



very good 



17° 



51' 



9 



faii- 



17° 



11' 



9 



good 



17° 



42' 



9 



' poor 



18° 



25' 



9 



fair 



18° 



26' 



12 



very poor 



■ 17° 



45' 



19 



fair 



16° 



48' 



Average 



fair to poor 



17° 



47' 



Calculated 





17° 



47' 



average. 



The calculated value of $ for this form is curiously in exact 

 agreement with the mean of the measurements. So, although 



3 'X 4 5 



this precise agreement is of course mere chance, it is near 

 enough to estalDiish the form and there are faces enough, well 

 distributed among the crystals, to confirm it. Its faces are 

 narrow and quite indistinguishable from the oscillation planes 

 with which it is associated. 



