*5 2 



POPULAR SCIENCE MONTHLY. 



Fig. 13. Plumose Quinidine. x 70 Diam- 

 eters. Polarized Light. 



Fig. 16. Cinchonidine. x 50 Diameters. 

 Polarized Light. 



Fig. 11. Platino-cyanide of Magnesia. 

 X 70 Diameters. Polarized Light. 





v. --■ *:\x, 





>$' V$ 



♦*:* V 



Fig. 17. Bichromate of Potash Crys- 

 tals. X 70 Diameters. Polarized Light. 



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Fig. 15. Crystal of CaC0 3 in India 

 Rubber Plant, x 120 Diameters. 



Fig. 18. Brucine Crystal. X 70 Diam- 

 eters. Polarized Light. 



