948 
term has its peculiar odour, which enables us to tell the one from 
the other by smelling. The odours of benzol and toluol, however, are 
somewhat alike. Both are empyreumatic, that of toluobis the stronger 
of the two. Xylol, on the other hand, has lost the empyreumatie 
character almost entirely, and exhibits an aromatic quality. This 
quality is more obvious still in pseudocumol, so that in this respect 
it bears some resemblanee to xylol. It seems to me that difference 
between xylol and pseudocumol is greater than that between benzol 
and xylol. Finally durol follows with an exclusively aromatic, phenol- 
like odour. 
The Combination-test. 
I feel convinced that a combination of the terms of the methyl- 
benzol series, without perceptible antagonism though weakening each 
other, may produce mixed smells, forming unmistakably a new 
unitary smell, though we still may trace in it the empyreumatic, 
respectively the aromatic quality of the component parts. It is rather 
Combination Cylinder-length Sensation 
Benzol-toluol . 0.30and0.50 cm.  __ toluol-tike 
ae 0.15 , 0.25 , B 
= 6 0.07 EDER (none) 
Benzo at Fe Bs RN faintly benzol-xylol-like 
blt | 0.07 - WaT (none) 
Benzol-Pseudocumol 0.20 , 0.60 , distinctly pseudocumol-like : 
~ = 0,15: -0,40 78 weak, doubtful odour 
Toluol-xylol 0.40 „ 0.50 , xylol-like 
5 5 AS 0.35 , > 
2 ka 0315 2, Fes = (none) 
Toluol-Pseudocumol 0.35 0E distinctly pseudocumol-like 
5 = 0.25 0,40. 5 Si = 
= » 0:15’ 5 B30", (none) 
Xylol-Pseudocumol 0:50, UBE, distinctly pseudocumol-like 
ie ~ OA, Oda weak mixture of pseudo- 
cumol and xylol 
» " 0.35 50:40 57 SA (none) 
