184 Dr. Walchner's Miner alogical and Chemical 



form (fig. 9), then the following proportion of inclination for 

 the base would pretty nearly approach the truth : 

 B'E:EC:CA= */23:7: 10. 



The inclination of the primary planes on the principal axis, 

 or the angle EAC, would, according to this proportion, be 

 = 34.° 59' 38", and the angles of the base B B' B = 1 1 1 ° 10' 6", 

 and B'BB' = 68 49' 5*". 



§6. 



Besides the primary planes, the bounding planes A, B', D, 

 D' occur in the crystals hitherto observed, the inclinations of 

 •which may be found immediately from the proportion of in- 

 clination on the base. The planes r' and r, on the contrary, 

 are secondary planes, from the second division of the vertical 

 edge-zones. The inclination of the planes r' which appertain 

 to the first vertical edge-zone, was ascertained with some 

 exactness. They answer to the secondary proportion 2CB': 

 3CA ; whence the sign B'Af belongs to them. The planes r 

 probably answer to an analogous secondary proportion in the 

 second vertical edge- zone. 



§ 7. 



The denotation of the different crystalline forms hitherto 

 observed in this mineral would consequently be, 



1. 2 A. 4D'. 4D. (fig. 1,2,3.) 



a d' d 



2. 2 A. 2 B'. 4 D'. 4 D. (fig. 4.) 



a b' d' d 



3. 2 A. 4 D'. 4 D. 4 B'Af. (fig. 5, 6.) 



a d' d r' 



4. 2 A. 4 D'. 4 D. 4 B'Af. 4 BAf ? (fig. 7.) 



ad' d r 



5. 8 P. 2 A. 4 D'. 4 D. (fig. 8.) 



p a d' d 

 The chief inclinations are, 



PonF=110° 0' 44" 

 a...d' = \30 18 56 

 a ...d =141 4 54 

 d'...d= 99 22 8 

 d...d = 77 50 12 

 d'...b' = 139 41 4 

 r'...a =119 29 47 

 r'...d' = 169 10 51 

 r'...r =121 26 



* 8 - 

 On a comparison of the crystallization of the hyalosiderite 



with 



