15 



First Sub-division. — Lustre metallic, (including semi or imper- 

 fect metallic.) 



1st. Section. — (Table 26.) — Always scratched by quartz, often 

 scratched by felspar, never scratched by apatite. 



2d. Section. — (Table 27.) — Always scratched by apatite, often 

 scratched by calc. spar, sometimes scratched by gypsum. 



Second Sub-division. — Lustre not metallic, (including semi or 

 imperfect metallic. 



1st. Section. — (Tables 28 and 29.) always scratched by quartz, 

 often scratched by felspar, sometimes scratched by apatite, never 

 scratched by fluor. 



1st. Sub-section. — Sp. gr. never below 4.5. 



2d. Sub-section. — Sp. gr. never above 5.0. 



2d. Section. — (Tables 30 and 31.) — Always scratched by fel- 

 spar, usually scratched by apatite, often scratched by calc. spar, 

 sometimes scratched by gypsum. 



1st. Sub-section. — Sp. gr. never below 3.5. 



2d Sub-section. — Sp. gr. never above 4.0. 



rouRTH GRAND DIVISION. (Table 32.) 

 No Divisions, Sub-divisions, nor sections. 



APPENDIX. 



No arrangement yet fixed upon. 



Directions for using the Tables, 



Having ascertained by reference to the page in which metallic 

 minerals are defined, that the mineral whose name, &c. he is in 

 quest of is metaUic, the student will at the same time determine 

 whether it be soluble in water or not. If soluble, it of course be- 

 longs to the fourth grand division, and nothing further is required 

 than to compare it with the few minerals which compose the 32d 

 table. If insoluble, as it most probably will be, he must make 

 experiments with the blow-pipe in order to determine 



1st. Whether the mineral in question be either entirely volatilr- 

 zable, or fusible with visible or odoriferous volatility. 



2d. Or whether fusible without the appearance of volatility, 



3d. Or whether infusible. 



