<>N WATF.U AND ITS COMPOUNDS 



51 



c<>M>isrs < f star-like clusters of several crystals, and also in 

 tin- half-incited scattered ice floating on rivers in spring time. At 



characterising separate, definite chemical compounds. The elements of crystallography 

 \vhi-h comprise a -)> < -i:il science, sh mid therefore be familiar to all who desire to work 



Fi<;. r,. Example <>t rhc form belonging to the FIG. 7. Rhombic Dodecahedron of the regular 

 regular system. Combination of an octahedron system. Garnet. 



an< I a cube. The former predominates. Alum, 

 thior spar, suboxide of copper, ami others. 



s. Hexagonal prism ti-nninati-d by hexagonal Fio. 9. Rhombohedron. Ca!c spar, 



>. Quaitz. &c. 



Fa;. 10. lihnmbic system. FK;. 11. Triclinia pyramid. 



Desminc. 



FIG. 12. Triclinic sv.-tt in. 

 AU.ite, fcc. 



in scientific chemistiy. In this work we shall only have occasion to speak of a few 

 crystalline forms, some of which are shown in Figs. 6 to 12. 



E 



