AN ARTICLE POR PRE- VENTING CHIMNEYS SMOAKING, WHICH I HAVE NAMED A SMOAK CONDUCTOR,' & WHICH MAY BE MANUFACTURED EITHER IN CAST IRON, WROUGHT IRON; COPPER, BRASS, AND TIN, OR ANY OTHER METALLIC SUBSTANCE
Year: 1812

page_text: FISHER'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
FISHER, of Oundle, in the County of Northampton, Ironmonger, send
greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Nineteenth day of
December, in the fifty-third year of His reign, give and grant unto me, the
said John Fisher, my exors, adñiors, and assigns, His especial licence, full
power, sole privilege and authority, that I, the said John Fisher, my exors,
adñiors, and assigns, should and lawfully might, during the term of years therein
mentioned, make, use, exercise, and vend, within England, Wales, and the
Town of Berwick upon Tweed, my Invention of "AN ARTICLE POR PRE-
VENTING CHIMNEYS SMOAKING, WHICH I HAVE NAMED A SMOAK CONDUCTOR,' & WHICH
MAY BE MANUFACTURED EITHER IN CAST IRON, WROUGHT IRON; COPPER, BRASS,
AND TIN, OR ANY OTHER METALLIC SUBSTANCE;" in which said Letters
Patent there is contained a proviso that if I, the said John Fisher, shall not
particularly describe and ascertain the nature of my said Invention, and in
what manner the same is to be performed, by an instrument in writing under
my hand and seal, and cause the same to be enrolled in His Majesty's High
Court of Chancery within two-calendar months next and immediately after the
date of the said Letters Patent, that then the said Letters Patent, and all
liberties and advantages whatsoever thereby, granted, shall utterly ceas
determine, and become void, as in and by the same (relation being thereunt.)
had) may more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said John,
Fisher, do hereby declare that the nature of my said Invention, and the manner
in which the same is to be performed, are particularly described and ascertained
in and by the Drawings in the margin hereof, and the following description
thereof (that is to say):-
The smoak conductor for enclosed chimnies is a box placed at the bottom of
such chimnies between iron covers, brick, or stone jambs; for chimnies not
inclosed, it is fixed with four (more or less) bolts.
Fig. 1 reprents the conductor for enclosed chimnies, and is circular or
stright on the plan, projecting from the back or fire grate about four inches;
it may be made to draw out and take down as convenience requires.
The front, if found necessary, can be made to hang with hinges. The dotted
lines show the situation of the funnel in the flow of the chimney. The door A
slides up and down in a groov placed for that purpose on each side, and to
facilitate its action, I place two springs at the back and two knobbs in the
front B, B; its use is either to encrease or diminish the draft.
2
Fig. 2 shews the conductor. The soffite C is made to fit the front of con-
ductor at D, D, and with the assistance of the grooved plates E, E, and screws
F, F, the soffite may be raised or lowered according to the height of the mantle
of the chimney. This part of the chimney being thus inclosed, and the current
of air stopped, its force is consequently encreased at the bottom of the conductor,
and the smoak necessarily ascends with greater rapidity. The perpendicular
tube G is fixed to the crown H; this tube is about seven inches diameter and
about eighteen inches long, can be made either square, round, or other con-
venient forms, but round I prefer; on the top of the tube G is the cap I, with
the two projecting voiders R, R. The cap I is about seven inches long, and'
the diameter and height may be varied, and also the diameter and length of the
tube, and if the tube be wanted crooked for any funnel, the same may be
done to suit the purpose.
The cap I is revited to the tube G by two iron straps, or supported by the
iron arms L, L, or any other method whereby the cap can be properly secured.
This cap may also be varied in form. After the smoak has passed through the
voiders R, R, the cover or top of the cap I prevents its return, by which
means a room may be kept free from smoak.
For chimneys not enclosed, the conductor must, it is evident, be made accord-
ing to the size of such chimnies, and the projection tubes, soffite, &c., made in
proportion.
Fig. 3 is the section of the conductor, where is shewn the width M, which
tends to give an additional force to the air and bottom of the conductor, but they