paper a H. Schumacher). In Ss cmuony: series, tthe ratio of the rotation, with 
| pressure, wontd be, with. a. series of closely related bodies, independent of ie 
p yressure. In order to test his supposition, Schumacher plotted the vapour tension 
Young. The bodies studied were: — The menthyl esters of acetic, propionic, -valeric, 
acetoacetic, methyl, ethyl and n-propyl acetoacetic, phenylacetic, phenylethylaceto= 
3 acetic, phenylacetoacetic, and phenylbenzoylacetic acids, furthermore, the myrtenyl 
. of crotonic and of hexahydrobenzoic acids. Bs 
3 The rule of Ramsay and Young applies within the limits of the experimental errors. 
T he tension curves may be calculated, with 1 percent. deviation, from Rankine’s 
fo mula: — logp = a—b/T. For particulars of the method and the results wa refer 
to ) the dissertation of the anHIOF (Basle, POs easy 
to ) about two-thirds of the absolute critical temperature, whereas Guye demonstrated . 
f furthermore that the absolute boiling point “in vacuo” approximates about one- ‘half of 
‘papers, and now W. P. Jorissen *) deals with the same subject in a epee entitled, “A | 
relation between boiling points under 1 atmosphere pressure and wm vacuo” ; 
a sige the relations found by Guye, the following ratio may be deducted: ac 
ss he ia Breede Ts@omm.) _ 
~ 0.78, Ree I es A) 
a>. — Ts(atm.) ee wes ) 
Z pproximately equal”. Jorissen calculated this ratio from 23 figures published by Guye. 
y R. Kempf’) the ratio for boiling points under 1 atm. pressure and “in vacuo’, amongst 
these the following of bodies which are of special interest for us: — | 
ad ; F t ‘ $ Ts) 
j _ Substance iene, yo PHL) rab 5 Cae ae B. p. (2). mm. : aaa 
1:2-Bromostyrene . . . 108° 20 219: to. 2219's 4 atm... <O:7% 
Methyl formiate . . . . 95° © 1O;to Lt 2199 os | tate 00S 
mcaprylic acid -..  .. ;-. 123.5 to 124.3°. 10 5 280: 40290 2 TORK 0h Ors 
DMEMEO re eC AG2O- DO Gh 90-10: 2929° Sr TOO: es OLR 
Thioborneol . . 94 to 95° eee Wek toe 225 ON TOO, vent OPE 
1-Methy! ketone of fornia. f Pirin aaa Siena op ha ae 
terpenylic acid . . . 205 to 210° Dan GOO 5 Gass Patiniose’ O00 
Car aphenilane aldehyde . 90° 10. 220° 1atm. 0.74 
Phenyl acetic acid. . . 144.2 to 144.8° MD io) 5265.09 1 atm. 0.78 
eee 149 to 155° a oa 291 to 294° 760 TT Oko 
Kessy! MeO aie AB t8s156° Bs grea 300 to 302° 1 atm. 0.75 
Kessyl ketone. . . . . 162 to 163° Phe B0a to! 8072.4 atm. 70:75 
eee Kanol glycol poise £ 17 to ac ed Os 281 to 2822: 760 0.78 
? 1) Arch. Sc. phys. et nat., Genéve (4) 36 1918), 36; Ghent: Zentral. 1918, Il, 597. — *) Bull. Soc. chim. 
4 (1890), 262. — %) Zeitsohr. f physik. Chem. 6 (1890), 374, _ 4) Zeitschr. f. anorgan. Chem. 94 (1916), 1; 
yi  s0165, 253; 96 (1916), 289. — *%) Ibidem 104 (1918), 157. —. ig Tabelle der wichtigsten organischen Ver- 
yndungen, geordnet nach den Schmelzpunkten. Braunschweig 1913. hae 
ee f y , t 7 
“ ’ 4 
r 2 
ag 
oe 
curves of 17 optically active bodies, which actually answered the rule of Ramsay and — 
- Some time ago, Ph. A. Guye?) and C. M. Guldberg’) found, Sitiepatidantly and heaily rey 
sit rcisaity, that the absolute boiling temperature, at 1 atmosphere pressure, amounts oe 
the absolute. critical temperature. Recently, W. Herz‘) drew general attention to. Meo ie 
as.» and Ts (atm. Standing for the absolute boiling points and the Sian NS mennie Jpop 
al ind found values between 0.71 and 0.84; furthermore, he calculated from data compiled __ 
