8 | E. BERNER. M.-N. KI. 
have to use constants determined from the optically active acids, and not 
those from the inactive acids, because one of these, the 122° acid, is a 
true racemic compound and the other one a pseudo-racemic conglomerate ; 
the first one having a density different from that of its components, and 
the other one the same density as its components. 
The constants of the 141° acid are: 4 
a:b:c- 2,1875: 1: 2,0794, B — 93 53' and the density d #14 
The density has later been determined by Prof. Goldschmidt and my- 
self to be 1,442. 
3 3 
By using the formulae: y = er N hæs ;@ =} cup 
Cc: sin ff a:c-sin D a:sin f 
J ee. ; 
and V= the molecular weight M being 182, I find: 
d’ 
For the act. comp. of the 122° acid y — 7,1960 y — 2,8322 w = 6,2920 
yc o. RE > » > I410 » » =6,6281 » =3,0300 » = 6,3001 
The melting-point curve between the inactive and the active acid has 
a form characteristic of the true racemic compounds.? The melting-points 
of different mixtures of the racemic- and the d-acid are as follows: 
100 0/, dextro-acid o 9/, rac. acid m.p. 95% 
95 > » » 5» » » » 93 0 
ae o» » » 25 » > » » OI 0 
60 » » » 40 » > » » Io2 9 
50 » » » 50 » » » » LÆS 0 
25 > » > 75 » » » » 11890 
O » » » IOO » » » » 122 0 
IL The Phenyl 3-bromo «-hydroxypropionic acid 
C;H;: CHBr: CHOH : COOH m. p. 165° and its 
optically active components. 
These acids are produced from the Phenylglycerinic acid 141 ? and 
its components by replacing the 8-OH with Br. 
Crystals of the racemic acid are obtained by the slow evaporation 
of a solution in absolutely dry ether. In crystallising the active compo- 
nents, chloroform was used as a solvent. 
1 Zeitschr. f. Kryst. u. Min. 55,123 (1915). 
? Roozeboom: Zeitsch. physikal. Chem. 28,494 (1899). 
