626 
MESSRS. T. E. THORPE AND J. W. RODGER ON THE RELATIONS 
slope. This is significant as indicating that even at this new condition of comparison 
the beliaviour of the alcohols, as at the comparable temperatures already employed, 
is anomalous. 
Corresponding Compounds. 
Iodide. 
Bromide. 
Chloride. 
Acid. 
Alcohol. j 
j 
i 
Diff. 
V- 
Diff. 
>h 
Diff. 
V- 
Diff. 
'/■ 
]\rotliyl. 
399 
26 
373 
109 
290 
Ethyl . 
404 
.36 
.368 
. , 
, , 
.34 
370 
Propyl. 
407 
3.5 
372 
42 
330 
17 
390 
i 
Butyl. 
• • 
•• 
• • 
• • 
379 
i 
Isopropyl. 
390 
37 
3.53 
36 
.317 
Isobutyl . 
404 
44 
360 
29 
331 
26 
378 
Ally]. 
40G 
35 
371 
43 
328 
Ethylene . 
455 
(.39) 
377 
; 
Corresponding iodides, bromides, chlorides, and acids now give constants which are 
closely related to one another. The large discrepancies given at the boiling-point by 
the lowest acids have now disappeared, and in all cases the differences between 
corresponding members of two different series of compounds are much more nearly 
constant, the largest variations being given by the acids. 
An iodide has, on the average, a coefficient which is 37 units greater than that 
of the corresjDonding bromide. Practically, the same average difference, 38, exists 
between corresponding bromides and chlorides. Here, the difference in -q is strictly 
proportional to the difference in molecular weight. The difference between an iodide 
and an acid, 26, on the avei*age, though uniform, is not so large as that between 
an iodide and a bromide, viz., 37, although the differences in the theoretical molecular 
weights are respectively 106 and 47. This indicates that in general q is not a 
simple function of theoretical molecular weight. Methyl alcohol, the only member 
of the alcohol series which could be included at slope ’0^323, gives a value considerably 
below that of methyl iodide or formic acid, the difference being in the direction of 
the change in molecular weight but showing no proportionality. Here, as with 
homologues, the relationships are much more regular than at the boiling-point. 
