374 Prof. Lewis, On the [May 14, 



Crystal 5. Fig. 5. 



a, d, s, co, b, c, o, p, g. 



Also rough pitted planes in zone [ds] adjoining b. 



The planes are all largely developed except p, s and co, but they 

 all give very poor reflexions. The corresponding planes o, g do not 

 lie accurately in a zone. 



Crystal 6. Fig. 10. 



a, 7), <f), d, t, co, x, a, i, o, c, ft, z, k, g, (12 1 12), (21 4 21) or (515), h. 



There is a doubtful plane p (139) on this crystal lying between 

 c and z and in the zone [ahg/3]. 



Crystal 7. Fig. 7. 



s, t, co, x, a, b, c, m, o, j3, z, k, h. 



There is a rough drawing of this crystal by Miller in a note- 

 book belonging to Brooke, which is a copy of that on the loose 

 papers already described ; and there is the following note by 

 Miller. " It is not worth while to attempt to give angles till all 

 the crystals are measured ; v, u, t, x, y and z are new." The planes 

 extant are those below the paper in the stereographic projection, 

 and to show these above by turning the crystal faces towards the 

 observer naturally places them in such a position as to encourage 

 Miller in his mistake. The cleavages a, m are fairly distinct. 



Crystal 8. 



a, c, M, o, /3, k, s, t, x, <r, i, g, p. 



The planes on this crystal are all much striated, and the mea- 

 surements obtained were poor. They, however, establish clearly 

 the tautozonal relations of the plane x. 



Crystal 9. Fig. 16. 



a, o, c, 7], cf), d, s, co, x, cr, i, /3, z, k, p, g. 



A small fragment with z and k comparatively large. It was 

 measured by Miller, but the solution was not completed. The 

 measurements agree closely with mine. 



Crystal 10. Fig. 12. 



a, o, b, g, d, s, t. 

 A very small crystal with distinct prismatic development, and 

 large o and b planes. 



Crystal 11. Fig. 6. 



d, s, t, co, x, ct, i, g, k. 

 A fragment imbedded in massive miargyrite. The planes are 

 all much striated. 



