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the development of smell, ‘as “Hele electrons. can 1 easily be shifted. In fact, the simple 
npounds| of all the metals are. inodorous, and if some complicated organic compounds 
; metals have a smell, it is not produced by vibrations of the valency electrons 
yetween the metal atoms, but Py the vibrations of those between other atoms of the 
molecule. | : 
With the aid on ‘his theory, he then explanent the indeuronanes: of various bodies, — 
~ such as methane, ethane, &c. As to the transmission of smell, he says that the mole- 
cules of the air take the smell, so that a volatilization of the smelling body itself would 
a not be necessary. So far the contrary has been believed, although it was difficult to — 
n nake this supposition agree with ‘the fact that it was impossible to prove any loss of 
weight with many strongly smelling substances, even if they had filled large rooms with 
‘their odour for some length of time. A further point against the old theory would be 
tt iat the smell of less volatile substances are in- may. cases spread much farther and 
much more. intensely by currents of air, than those of very volatile bodies. The author 
"mentions, besides, that certain animals can scent the smell of man from a distance. 
and that it is recognized by dogs days afterwards in the footprints. lf this smell was 
caused by odorous matter, separated from the human body, it is Teudt’ cS opinion that — 
this substance, on the one side, would have to be rather heavy SO as to prevent its 
being carried away, whereas on: the other. side it would have to be light, in order to 
be carried far off by the wind. This contradiction was to. be solved with the aid of 
his theory, according to which the vibrations of the smell ‘of man are taken up the Cg 
same by those air molecules carried ayey by the wind, as. by ore clinging to the 
soil, owing to adhesion. 
Teudt points out that the vibrations ‘odilded in the air i moreciies by odorous 
‘substances make themselves conspicuous by changing the physical behaviour of the — 
air, in that its power of absorption for radiated heat is considerably increased by — 
‘conducting it over smelling bodies. According to Tyndall’ s*) experiments, patchouly — 
it ncreased 30 times and anise even 372 times the power of absorption of ordinary dry 
air, without the air having taken up any ponderable quantities of these substances. 
This phenomenon, unexplained so far, comes about, _according to Teudt, through the ~ 
destruction of part of the heat ‘Tays, because they interfere with the vibrations of the 
electrons produced in the air molecules by odorous bodies. Teudt further succeeds in. 
: “explaining, with the aid of his theory, the fact that, with many homologous ranges 
oO organic compounds, - the quantities which ‘it is possible to notice decrease with 
increasing molecular weight, but we must refer our readers | to the cred tor more 
pa Beulars: ° bis oN 3, 
. 2 Z f i ; j 
4 “Der Duft als analytisches Kennzeichen” (Smell as an analytical mark of distinction) is 
the heading of an article by H. Heller”), with the contents of which we agree throughout. 
The author lays stress upon the fact that, in the description of chemical bodies, the © 
s mell is generally not mentioned, unless it is specially remarkable. He ascribes this | 
to the disinclination of chemical men to indicate as characteristic in every case such 
‘properties as are more or less subjective and cannot be expressed. by figures. Those, 
however, whose domain is the chemistry of the aromatics, are of a different opinion 
and assign to the smell the same importance as to the colour and, to a certain extent, . 
that of the data expressible in figures. For instance, the characterization of compounded 
flov er oils with espe data is difficult, if BOF impossible, as long: as not all the 
‘te » 
ion > 
> A : 7 
> 4 The heat, looked spon as a kind at iactiahi 1875, Heer i Be. — *) Deutsche Parf.-Ztg. 5 (1919), 91. 
ag 
