12 E. BERNER. M.-N. KI. 
III. The Phenyl ?-bromo «-hydroxypropionic acid 
C,;H;- CHBr : CHOH - COOH m. p. 157° and its optically 
active components. 
In analogy with the stereoisomeric acids, these compounds are ob- 
tained from the Phenylglycerinic acid 122° and its components by repla- 
cing the $-OH with Br. 
As a solvent for the racemic acid are used ether, for the components 
chloroform. 
The racemic acid. 
Melting-point 157 9. 
Specific gravity 1,674. 
Class of symmetry: monoclinic-prismatic or monoclinic-domal. 
Axial angle # — 990-217 
Ratio of axes: a: DE — 7,684 1 20,976: 
All the crystals examined are twins, with the face a (100) as a twin 
plane. 
The appearance of the crystals is as in fig. 4, but without the face x. 
The twin nature is, as by the isomeric acid, betrayed by the presence of 
a re-entrant angle between the two basal planes. 
Forms observed: a j100|, c }ooıl, m j110l, f |310l, v }1271. 
As the crystals are small and badly developed, a large number had 
to be measured. The results of the measurements of 29 species are 
given in the following table: 
Table E 
No. of | 
Angle | Measure- Limits ducam | Calculated 
ments De | 
ge E Toy | 
(100) : (310) 43 300 1°—320 30° SD pe M = 
(100) : (oor) | 28 85- 55 —87 28 | 86 39 * | = 
[oıo] :[or1] rr | 25 39 —27 26 | 26 44 * — 
(100) : (110) NC | 59 18—62 7 | 60 52 | 610 6' 
(roo) : (12 1) I2 | 76 30—78 4o | 11 43 | 71 35 
[oor]: [oro] = = | ca. 900 | 99 oO 
Cleavage, imperfect parallel to # joro! and c joor|. 
The plane of the optic axes is nearly perpendicular to the face a (100). 
The first median line lies in the a-c plane. 
