AN IMPROVED POT FOR CHIMNEYS AND VENTILATION
Year: 1858

page_text: LETTERS PATENT to William Spence, of 50, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "AN IMPROVED
POT FOR CHIMNEYS AND VENTILATION."-A communication.
Sealed the 20th July 1858, and dated the 28th January 1858.
PROVISIONAL SPECIFICATION left by the said William Spence at the
Office of the Commissioners of Patents, with his Petition, on the 28th
January 1858.
I, WILLIAM SPENCE, of 50, Chancery Lane, in the County of Middlesex,
Patent Agent, do hereby declare the nature of the said Invention for "AN
IMPROVED POT FOR CHIMNEYS AND VENTILATION" (being a communication. from
abroad), to be as follows:-
This Invention consists in manufacturing pots of clay or materials suitable
for chimney pots in such manner as that the mouth for the exit of the smoke
or air may be protected, and the smoke or air within the pot. receive an
upward instead of a downward tendency from the action of the wind- or
current of the external atmosphere. This is effected by providing the pot
with an upper or outer lip or cap projecting above at a small distance from
the inner or ordinary shaft, and placing around or externally to. such inner
shaft a space or a series of spaces, so situate in reference to an inclined
surface below that the wind or external current of the atmosphere will be
deflected upwards through those spaces, and counteract the tendency to a

page_text: downward current, which such wind. would otherwise produce at the mouth of
the inner shaft if not protected,, and thus, aid: the up current of the inner or
ordinary shaft. Such pots may be made of any shape, and present an orna-
mental appearance externally, and be adapted to the style of architecture of
the building upon which they are placed.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Spence in the Great Seal Patent Office, on the
28th July 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
SPENCE, of 50, Chancery Lane, in the County of Middlesex, Patent Agent,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of January, in the year of our
Lord One thousand eight hundred and fifty-eight, in the twenty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Spence, Her special license that I, the said William
Spence, my executors, administrators and assigns, or such others as I, the
said William Spence, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "AN IMPROVED POT
FOR CHIMNEYS AND VENTILATION," being a communication from abroad, upon
the condition (amongst others) that I;' the said William Spence, by an instru-
ment in writing under my hand and seal, should particularly describe and
ascertain the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great 'Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
1:
NOW KNOW YE, that I, the said William Spence, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawings hereunto annexed, and to the
letters and figures marked thereon (that is to say) :-
This Invention of "An Improved Pot for Chimneys and Ventilation"
consists in manufacturing pots of clay or similar materials suitable for chimney

page_text: pots in such manner as that the mouth for the exit of the smoke or air may
be protected, and the smoke or air-within the pot receive an upward instead
of a downward tendency from the action of the wind or current of the external
atmosphere. This is effected by providing the pot with an upper or outer lip
or cap projecting above and at a small distance from the inner or ordinary
shaft, and placing around or externally to such inner shaft a space of a series
of spaces, so situate in reference to an inclined surface below that the wind
or external current of the atmosphere will be deflected upwards, and make an
upward current through those spaces, and counteract the tendency to a down-
ward current, which such wind-would-otherwise produce at the mouth of the
inner shaft if not protected, and thus aid the up current of the inner or
ordinary shaft...Such pots may be made of a square, circular, hexagonal, or
other shape, and present an ornamental appearance externally, and be adapted
to the style of architecture of the building upon which they are placed.
Having thus stated the nature of the Invention, I will proceed to describe,
by reference to the accompanying Drawings, the construction of a pot of
dimensions suitable for general use.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a vertical section, and Fig. 2 a plan or horizontal view, of a
cylindrical pot; Fig. 3 is a plan view of a pot of hexagonal form, and Fig. 4
represents a square pot. a is the ordinary shaft for the escape of the smoke
and heated air; 6 is the inclined surface by which the external current of the
atmosphere is deflected upwards, such inclined surface being placed at an
angle of about forty-five degrees to the vertical side of the pot; c is the outer
cylinder shaft or cap surrounding the inner shaft a, the upper portion or lip
of which cylinder rises a small distance above the upper edge or lip of the
inner shaft. Between the outer surface of the inner shaft and the inner
surface of the outer cylinder or cap are spaces d, d, d, made by the fillets
e, e, e, which support the outer cylinder or cap, and connect it with the inner
shaft. The current of the external atmosphere striking against the inclined
surface will be deflected upwards, and create an upward current in the
space or spaces d between the outer surface of the inner shaft a and the inner
surface of the outer cylinder or cap; this upward current meeting the ordinary
current of the atmosphere as it blows across the top or upper edge or lip of
the outer cylinder or cap, will prevent any excess of pressure downwards, and
tend to aid the up current in the shaft.
In Figures 3 and 4 it will be seen that the spaces d are formed between the
flat sides of the hexagon and square respectively of the inner or ordinary shaft

page_text: a, and the concave surface of the external cylinder or cap c, which is sup-
ported and connected with the inner shaft, at the angles of the internal shaft.
Fillets may be placed at the angles of the internal shaft for the purpose of
increasing the size of the spaces.
Having thus described the nature of the said Invention communicated to
me as aforesaid, and in what manner the same is to be performed, I would
have it understood that what I claim under the above in part recited Letters
Patent is, the manufacture of a pot for chimneys and ventilation, having an
inclined surface in combination with an outer and inner cylinder or shaft, so
arranged as that the mouth of the inner shaft may be protected and relieved
from pressure, as above described.
In witness whereof, I, the said William Spence, have hereunto set my
hand and seal, the Twenty-seventh day of July, in the year of our
Lord One thousand eight hundred and fifty-eight.
Witness,
GEO. BEDELL COULCHER,
50, Chancery Lane,
Law Stationer.
WILLIAM SPENCE. (L.S.)