384 MM. W. C. Broffffer and Gr. vom Rath on certain 



(measuring along the axis a 12 centims., along the axis b 20 

 centims.) snows undoubted rhombic symmetry. We have de- 

 termined the following faces : — 



e ={a : 2b : e), P2, 

 «=(a:f&:e), $P£ 



■v/r = ( oca : 66 : c), -JF ac, 

 7 = ( oca : 7 : c ) ? |.p oc ? 

 k = ( oca : 26 : c), ^P oo, 

 q =( oca : §6 : c), §P ac, 

 m=.(aib : ccc), ccP, 

 a =(a : c*6 : co c) ^Poc, 

 6 = ( oca : 6 : occ), oo P oc, 

 c =(aca : cc6 :c) ; OP. 



The faces denoted by Latin letters are already known on 

 the enstatite from Breitenbach and on the hypersthenes from 

 Laach and Capucin. The faces denoted by Greek letters are 

 new. The fig. 4 represents the crystal in question with all 

 deformities. The following angles were measured with the 

 contact-goniometer.. It will be seen that they compare satis- 

 factorily with the values calculated from the elements of the 

 Breitenbach enstatite. 







Measured. 



Calculated. 



m 



: m' (upon 6) = 88° 



88° 16 



k 



: b 



= 105 50 



105 56 



9 



:b 



= 111 



110 501 



7 



:b 



= 99 30 



99 16 



ylr 



: b 



= 95 30 



95 26 



€ 



: h 



= 150 30 



147 31 



e 



: b 



= 122 30 



123 16 



e 



: b 



= 105 



103 49 



e 



: a 



= 119 30 



119 31 



e 



: 7 



= 151 45 



149 49 



e 



:* 



= 150 



148 51 



e 



: h 



= 152 



150 29§ 



Only two of these measurements (e : k and e : 7) show a 

 considerable divergence from the calculated angles. It is to 

 be explained by the difficulty and uncertainty involved in 

 faces perturbated by oscillation and vaulting. 



