NUCLEAR CONDENSATION OF CERTAIN ORGANIC VAPOURS. 461 
Alcohol. Supersaturation. Difference. 
Ethyl*.2-56 
Propyl.3 ‘03 (P47 
Iso-butyl. 3 - 66 0 - 63 
Iso-amyl.404 0‘48 
The acids and esters require a larger supersaturation to produce condensation in 
ionised air than the alcohols do. With the exception of iso-valeric acid, the acids 
require larger supersaturations than the esters—the supersaturation for formic and the 
butyric acids being extraordinarily large. One would have expected the association 
existing in the molecules of the vapour of acetic and some of the other acids to 
facilitate condensation. 
The relations existing between chemical constitution and supersaturation will be 
seen from the following :— 
Esters. 
s. 
Alcohols. 
S. 
.. 
Acids. 
s. 
( 1 ) CH 3 -C-O-C 2 H 5 
8-9 
( 12 ) CH 3 -OH 
3-12 
( 6 ) H-CO-H 
25 • 1 
II 
II 
0 
0 
(2) C 3 II 7 -C-O-CH 3 
5-3 
(13) CffU-OH 
2-56 
(7) CH 3 -C-O-H 
11 
9-3 
0 
II 
0 
(3) (CH 3 ) 2 CH-C-0-CH 3 
5-2 
(14) C 3 H 7 -OH 
3-03 
( 8 ) C 2 H 5 -C-O-H 
|| 
9-4 
0 
II 
0 
(4) CH 3 -C-0-C 3 H r 
5-1 
(15) (CH 3 ) 2 CH-CH 2 -OH 
3-66 
(9) C 3 H 7 -CO-H 
15-0 
II 
II 
0 
0 
(5) C 2 H 5 -C-O-C 0 H 5 
7-8 
(17) (CH 3 ) 2 -C 3 H 5 -OH 
4-14 
(10) (dUyCH-CO-H 
13-3 
II 
h 
0 
6 
H-OH 
4-2 
( 11 ) (CH 3 ) 2 -CH-CH 2 -CO-H 
6-0 
0 
The general nature of the affect of a given group of elements on the magnitude of S 
may be stated thus :— 
Carbonyl , ^>C = O. The presence of this radical is associated with a large S, as 
shown by the acids and esters. 
Alkyl-g roups, CH 3 - 5 C 2 H 5 -, C 3 H 7 - (CH 3 ) 2 CH-, (CH 3 ) 2 *CHCH 2 -, C 6 H n -. The 
presence of these appears to contribute only a small amount to the value of S. The 
regular increment in S for ethyl, propyl, iso-butyl, and iso-amyl alcohols indicates that 
* Using y = 1 • 404 in each calculation. 
