DE. A. W. HOFMANN ON THE PHOSPHOEHS-BASES. 
417 
Forms observed 
(z:oo5:oo(?; ooo!:J:coc; oofl!:co5:c; a:5:coc; oo a', b'. c', a\b\ c. 
According to Levy : — ■ 
MM=:84°42'; MP=94®34'; 5 : A=1 : 0-9869. 
Forms observed : — ■ 
A', g\ P, M, e'tZi 
Combinations observed : — 
110, 0 01 (Fig. 2). 
110, 001; 100 (Figs. 3 & 4). 
110, 001; 10 0, 010 (Fig. 5). 
0 01, 1 0 0, 110, IIL 
001, 10 0, 110, 111; oil. 
001, 10 0, 110, 111; oil, 010 (Fig. 6). 
Fig. 2. Fig. 3. 
Hemitropic crystals with the axis of hemitropy [1 0 0], with the face of hemitropy 
0 01 = 0 P (Naumann)=oo a\cGb: c (Weiss)=P (Levy). 
Fig. 7. Fig. 8. Fig. 9. 
The hemitropic crystals are sometimes simple, as in Fig. 7 ; sometimes complicated, 
as in Fig. 8. It is then difficult to distinguish them from trimetric crystals ; they be- 
come, however, intelligible by assuming that they result from four hemitropic crystals 
MDCCCLX. 3 K 
