September 1784

If the Room has no Fire Place and is too close to burn
charcoal, it may be kept boiling while it is playing on the
infected Places (if the Engine is made of Copper or Tin) by a large
heated Iron placed under it

It will be necessary while this is performing, that every door
Window or Aperture that has not an immediate Communication
with the external Air be close stopt, and as many Openings next
the external Air be left open as can with conveniency be
admitted, that as the rarified impure Air is forced out, as
much of the pure fresh Air may supply its Places as possible
The opening & shutting of the different Out and Inlets must
be strictly attended to.

By the above method, what Air is left impure after the
Rarifaction of the boiling Vinegar, will be in a great measure
corrected by the Showers of Vinegar falling through it. But
as this method will render such Rooms as are at the Time
inhabited too wet to warrant such a Procedure, the following
might be substituted, particularly where no Fire or Fire place
is allowed

Let a wide shallow Tub (or what is more commodiously
used, The Machine a Description of which is here annexed)
that has its Bottom perforated full of small Holes, be placed on
Supporters as near the Ceiling as is convenient to pour in cold
Vinegar, and another on the Floor, somewhat wider, immediately
under the first, to receive the Liquor as it falls; which will
serve repeatedly in different parts of the Room, till it has
past through most of the confined Air.

Firing Gunpowder will tend much to purify infected
Places, as the Explosion will force out a considerable Column
of Air, and make room for the admission of fresh, provided
there is a Communication with the external Air as above
recited; and the Smoke will be the Acid of Sulphur.

And as a considerable Portion of fixed Air is generated
in the Bodies of Men, and thrown out by the Mouth as
excrementitious; the passing of Lime Water through it,
occasionally, as the Vinegar is directed to be Done will tend