me Nature, when the
_Plague_ was carried at once out of _Provence_ several Leagues into the
_Gevaudan_. Usually indeed the _Plague_, especially when more violent
than ordinary, spreads from infected Places into those which border upon
them: which probably is sometimes effected by some little Communication
infected Towns are obliged to hold with the Country about them for the
sake of Necessaries, the Subtlety of the Venom now and then eluding the
greatest Precautions; and at other times by such as withdraw themselves
from infected Places into the Neighbourhood.

I OWN it cannot be demonstrated, that when the _Plague_ makes great
Ravage in any Town, the Number of Sick shall never be great enough to
load the _Air_ with infectious _Effluvia_, emitted from them in such
Plenty, that they may be conveyed by the Winds into a neighbouring Town
or Village without being dispersed so much as to hinder their producing
any ill Effects; especially since it is not unusual for the _Air_ to be
so far charged with these noxious _Atoms_, as to leave no Place within
the infected Town secure: insomuch that when the Distemper is at its
Highth, all shall be indifferently infected, as well those who keep from
the Sick, as those who are near them; though at the beginning of a
_Plague_ to avoid all Communication with the Diseased, is an effectual
Defence. However, I do not think this is often the Case: just as the
_Smoak_, with which the _Air_ of the City of _London_ is constantly
impregnated, especially in _Winter_, is not carried many Miles distant;
though the Quantity of it is vastly greater than the Quantity of
infectious _Effluvia_, that the most mortal _Plague_ could generate.

BUT, to conclude what relates to the _Air_, since the ill Qualities of
it in these _Northern_ Countries are not alone sufficient to excite the
_Plague_, without imported _Contagion_, this shews the Error of a common
Opinion, countenanc'd by Authors of great Name[60], that we are
necessarily _visited_ with the _Plague_ once in thirty or forty Years:
which is a mere Fancy, without Foundation either in Reason or
Experience; and therefore People ought to be delivered from such vain
Fears. Since the _Pestilence_ is never originally bred with us, but
always brought accidentally from abroad, its coming can have no relation
to any certain Period of Time. And although our three or four last
_Plagues_ have fallen out nearly at such Intervals, yet that is much
too short a Comp