A CONTRIVANCE FOR BETTER ENSURING THE EGRESS OF SMOKE AND BARIFIED AIR IN CERTAIN SITUATIONS
Year: 1824

page_text: CROSLEY'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
CROSLEY, of Cottage Lane, City Road, in the County of Middlesex, Gentle-
man, send greeting.
WHEREAS His most Excellent Majesty King George the Fourth, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Fourth day of November, in the fifth year of His reign, did,
for Himself, His heirs and successors, give and grant unto me, John
Crosley, my exors, admors, and assigns, His special licence, full power, sole
privilege and authority, that I, the said John Crosley, my exors, admors,
and assigns, or such others as I, the said John Crosley, my exors, admors,
or assigns, should at any time agree with, and no others, from time to time
and at all times during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, my Invention of "A CONTRIVANCE FOR
BETTER ENSURING THE EGRESS OF SMOKE AND BARIFIED AIR IN CERTAIN SITUATIONS,"
within that part of the United Kingdom of Great Britain and Ireland called
England, the Dominion of Wales, and Town of Berwick upon Tweed;
in which said Letters Patent there is contained a proviso obliging me, the
said John Crosley, by an instrument in writing under my hand and seal, par-
ticularly to describe and ascertain the nature of my said Invention, and in
what manner the same is to be performed, and to cause the same to be
inrolled in His Majesty's High Court of Chancery within six calendar months
next and immediately after the date of the said recited Letters Patent, as in
and by the same, reference being thereunto had, will more fully appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
John Crosley, do hereby declare that my said Invention consists of an
arrangement in the construction of a ventilator or chimney top for better
ensuring the egress of smoke and rarified air in exposed situations, which
arrangement I effect in the following manner :-
Upon the top of the flue or chimney or other channel intended for the egress
of the smoke or rarified air, I affix a cylindrical rim in a perpendicular position,
the diameter of which will be ascertained by the size of the flue, chimney, or
other channel to which it is attached, and its height may be about one half of
its diameter; around and to the top of this cylindrical rim is affixed an inverted
frustum of a cone, the smaller diameter of which is of course defined by that of
the rim to which it is joined, and the diameter of the upper or widest part is about
two fifths larger than the lesser diameter, the perpendicular depth about three
tenths of the lesser diameter, and the depth of the side about one third of the
lesser diameter; over this is a concave cap or cover whose diameter may be
about one third larger than that of the cylindrical rim, and its depth about one
fifth of its own diameter, having an aperture in the centro of it about one half
of its diameter; to the outer circumference or border of which cap or cover is
attached an inverted frustum of a cone, the lower or smallest diameter of which
is just sufficient to admit of its being passed down close over the frustum of a
cone already secure:1 to the cylindrical rim; its perpendicular depth, and the
depth of its side being of the same dimensions as those of the first-mentioned
frustum. This concave cap or cover, with the inverted frustum of a cono
attached to it, may then be passed down over the frustum of a cone fixed to
the cylindrical rim, until the bases of the two inverted frustums aro brought
nearly to the same level; it is then secured in that position by pillars or stays
rivetted or otherwise attached, one end to the cylindrical rim, and the other to
the concave cap or cover; around the aperture in the centre of the cap or cover
already mentioned another cylindrical rim is affixed in a perpendicular position,
the height of which may be about one fifth of its own diameter; over this
another cancave cap or cover, the diameter of which may be about thrco fourths
of the one first mentioned, and its depth about one fourth of its own diameter,
i supported by pillars or stays, as before, at such a height as to bring the circum-
ference or border thereof a little below the level of the top of the last-mentioned
cylindrical rim. The object of this arrangement is to prevent any gust or gale
of wind blowing horizontally across the top of the flue or chimney, and thereby
obstructing the egress of the smoke or rarified air. And I do hereby declare
that the nature of my said Invention, and the manner in which the same
is to be performed, are also particularly described and ascertained in and by

page_text: the Drawings hereunto annexed, and the following description thereof (that is
to say):-
--
Upon the top of the flue or chimney, or other channel intended for the egress
of the smoke or rarified air, I affix in a perpendicular position a cylindrical
rim G, G, described in Figures 1 and 2, the diameter of which will be ascer-
tained by the flue, chimney, or other channel to which it is affixed, and its
height may be about one half its diameter; around and to the top of this
rim G, G, is affixed an inverted frustum of a cone H, H, the smaller diameter
of which is defined by that of the rim G, G, to which it is attached; and the
diameter of the upper or widest part is about two fifths larger than the lesser
diameter, and its perpendicular depth about three tenths of the lesser diameter,
and the depth of the side about one third of such lessor diameter; over this is
a concave cap or cover J, J, the diameter of which may be about one third
larger than the diameter of the rim G, G, and its depth about one fifth of its
own diameter, having an aperture in the centre of it about one half of its
diameter. To the outer circumference or border of this cap or cover is attached
an inverted frustum of a cone K, K, the lower or smallest diameter of which
must be just sufficient to pass over the frustum of a cone H, H, as closely as
possible; its perpendicular depth and the depth of its side being of the same
dimensions as those of the frustum H, H. This cap or cover J, J, K, K, may
then be passed down over the frustum H, H, until the bases of the two inverted
frustums H, H, and K, K, are brought nearly to the same level. It is then
secured in that position by small pillars or stays I, I, rivitted or otherwise
attached, one end to the cylindrical rim G, G, and the other to the cap or
cover J, J; around the aperture in the centre of the cap or cover J, J, another
-cylindrical rim L, L, of the same diameter as the aperture, is affixed in a perpen-
dicular position, the length of which may be about one fifth of its own diameter;
over this another concave cap or cover N, N, N, the diameter of which may
be about three fourths of the cap or cover J, J, and its depth about one fourth
of its own diameter, is supported by pillars or stays M, M, at such a height
to bring the outer circumference or border thereof a little below the level of the
top of the rim L, L, so that no gust of wind can pass directly across through
the upper part of the flue or chimney, while sufficient space is left open for the
egress of the smoke and rarified air. The red dotted lines in Figure 1 aro
intended to shew the course by which the smoke and rarified air make their
escape; and Figure 3 is merely a shaded elevation of the contrivance when
complete, and ready to be affixed to the flue or chimney. I do not mean or
intend hereby to limit myself to the employment of any particular material or
materials in the construction of the several parts described, but to avail myself
13

page_text: of any materials which are fit and proper for the purpose; I may also observe
that the plan, as described, may be varied by substituting cylindrical, spherical,
or other geometrical figures or combinations thereof, such as would naturally be
suggested by the above description to persons conversant with the subject,
whereby a sufficient protection may be afforded for the egress of the smoke and
rarified air.
In witness whereof, I have hereunto set my hand and seal, this Twenty-
seventh day of April, in the year of our Lord One thousand eight
hundred and twenty-five.