J. C. W. Ilumfi'ey. 
Fig. 13. Twiii.s X 45. 
Phil. Trnus.. . 1 . vnl. l'OO, Pla.fi' 4. 
Fig. 14. 4’wins x 45. 
Fig. 15. A single cry.stal after .straining 
in tension and re-etcliing x 5. 
Fig. 10. Same after cooking 5 minutes 
at G(r C. 
Fig. 17. Same after 10 minutes at GO C. 
'a 
