308 
A combined graph of Tables I and II may be obtained by plotting 
the molecular weights against either the logarithms of the specifie 
smell intensities or the critical distances. The curves will then be 
seen to rise correspondingly and to run roughly parallel. 
TABLE i's 
Critical distance (cm.) 
Fatty acids a TE NE SE 
ER aee 4 /29 n Ion. '/go n. “h60 N.i"/3 TM.) "ego 1 
Formic acid 1:2 no charge ; — 
Acetic acid 20 0.5 2 
Proprionic acid | 81 50 | 20 
Butyric acid 125 | 85 74 
Valerianic acid | 170 173 | 18 
Capronic acid | — 190 180°) 177.160.) 1324 “106 
| 
Caprylic acid “= | — = 24 a = 90 
N. B. Below '/y n. great care has been taken to keep up the spraying 
precisely '/; min. 
Fatty acids re 7 
£3 « critical distance 
4 
SS a 
Sun Il. int. (logarithm) 
q Ns smell, int, (logarithm 
Nd ee 
Se 
ee ee ae 
formic- acetic- propr:onic— butyric- valerianic- caproic- oenanthylic- caprylic- 
acid acid acid acid acid acid acid acid 
Fig. 2. 
A combined graph of Tables I] and IV may be obtained by 
plotting the molecular weights against either the logarithms of the 
specific smell intensities, or the critical distances. The curves thus 
obtained are not so regular and similar as in the case of alcohols, 
nevertheless they are of the same type. 
Our object in doing this is to compare a physiological with a 
= 
