steams with that liquor, and thereby affecting the nerve, or perhaps by
insinuating themselves into the juices of the brain, after the same manner,
as I have in the following Observations intimated, the parts of Salt to
pass through the skins of Effs, and Frogs. Since, I say, smelling seems to
be made by some such way, 'tis not improbable, but that some contrivance,
for making a great quantity of Air pass quick through the Nose, might at
much promote the sense of smelling, as the any wayes hindring that passage
does dull and destroy it. Several tryals I have made, both of hindring and
promoting this sense, and have succeeded in some according to expectation;
and indeed to me it seems capable of being improv'd, for the judging of the
constitutions of many Bodies. Perhaps we may thereby also judge (as other
Creatures seem to do) what is wholsome, what poyson; and in a word, what
are the specifick properties of Bodies.

There may be also some other mechanical wayes found out, of sensibly
perceiving the _effluvia_ of Bodies; several Instances of which, were it
here proper, I could give of Mineral steams and exhalations; and it seems
not impossible, but that by some such wayes improved, may be discovered,
what Minerals lye buried under the Earth, without the trouble to dig for
them; some things to confirm this Conjecture may be found in _Agricola_,
and other Writers of Minerals, speaking of the Vegetables that are apt to
thrive, or pine, in those steams.

Whether also those steams, which seem to issue out of the Earth, and mix
with the Air (and so to precipitate some _aqueous_ Exhalations, wherewith
'tis impregnated) may not be by some way detected before they produce the
effect, seems hard to determine; yet something of this kind I am able to
discover, by an Instrument I contriv'd to shew all the minute variations in
the pressure of the Air; by which I constantly find, that before, and
during the time of rainy weather, the pressure of the Air is less, and in