120 Dr.S. B.Schryver. Some Investigations Dealing [Aug. 12, 
the phases. The lower the surface tension of the salt solution therefore, the 
lower should be the critical solution temperature. This hypothesis is fuliy 
borne out by the results recorded in the accompanying table. 
Fifteen grammes of crystalline phenol were mixed with 25 c.c. of N/10 salt 
solutions in a wide-mouthed test-tube provided with a stirrer, and with a 
thermometer inserted into the mixture. This was inserted into a litre beaker 
containing water, which was also provided with a stirrer, and which was slowly 
heated on a sand bath; boththe mixture in the test-tube and the water were con- 
tinually stirred the whole time. As critical solution temperature is arbitrarily 
chosen that point at which the phenol-salt solution mixture is converted from 
an opaque to an opalescent fluid, a process which takes place within the interval 
of one-tenth of a degree. On further heating the opalescent fluid gradually 
becomes clear; on cooling again, with continual stirring, opalescence and final 
opacity reappear, and the point at which the opalescent fluid becomes opaque 
is only a fraction of a degree lower than the point observed when the change 
took place in the reverse direction. 
With normal solutions of the salts of lower surface tensions, such as sodium 
trichloracetate, the system is monophasic even at quite low temperatures (4° C.). 
Table I—Critical Solution Temperatures of Phenol and N/10 Salt Solutions. 
Solutions. Temperature. Solutions. Temperature. 
Sodium’ chloride si2sa...4 aces 74°3 Sodium formaters. ure cee 70:0 
53. sOROMIGE.. oss nee (pert ae, TACtAbe } a..ccee eae 68 °5 
53. o mitrate..cGe ce ene 71°8 peMracetatel sicoe.cae. eae 66 ‘9 
yt AOGIdG,.nc.ceasaee reece: 7feh A »  monochloracetate...... 66 °1 
»,  sulphocyanide ......... 68 °2 »  dichloracetate ......... 63 *1 
»  trichloracetate ......... 58 ‘0 
ibithium ‘chloride = ..).....06. 5-7 74°3 PM MMDENZOALE <2. costae 49 +1 
POtassiim 4. sh. gact see 73 °2 ina, Salicylate) <2). 2 sae 49 °3 
Mapmestiim: 30°) ic.qcce 75 °2 a malonate. v0.0, violet CEL 
Calcium Syne, NiWccmetecs tetas 75 ‘0 Par Succinate’ /.t.c.cccseee 748 
Sirontigm: |, oy yak eeose oe 749 Bs atartrate icq cdewh meee Tiel 
Barium aL beeen enes 75 °0 Ber sCitrate.- <i ..tsj eee 77 ‘0 
3) Chlorides) }..h tea nar 74.°3 
Solubility of Crystalline Substances in Salt Solutions. 
The benzamide, caffeine, and -toluidine were Kahlbaum’s preparations. 
The phenylalanine was prepared synthetically by the method of 
E. Fischer.* } 
The d.l. leucine was prepared directly from commercial isoamyl alcohol. 
From the latter, isovaleraldehyde was prepared by the method of Bouveault 
and Rouszett by dropping the alcohol into a warmed bichromate mixture 
* ¢Ber.,’ 1904, vol. 37, p. 3062. 
+ ‘ Bulletin de la Soc. Chim.,’ [3], vol. 11, p. 301. 
