AN IMPROVED CAP OR COVER FOR THE GLASSES OF GAS AND OTHER LIGHTS
Year: 1857

page_text: LETTERS PATENT to George Brooks Pettit and Henry Fly Smith, of
Oxford Street, in the County of Middlesex, Gas Engineers, for the
Invention of "AN IMPROVED CAP OR COVER FOR THE GLASSES OF GAS AND
OTHER LIGHTS."
PROVISIONAL SPECIFICATION left by the said George Brooks Pettit and
Henry Fly Smith at the Office of the Commissioners of Patents, with
their Petition, on the 1st August 1857.
We, GEORGE BROOKS PETTIT and HENRY FLY SMITH, of Oxford Street,
in the County of Middlesex, Gas Engineers, do hereby declare the nature of
the said Invention for "AN IMPROVED CAP OR COVER FOR THE GLASSES OF GAS
AND OTHER LIGHTS," to be as follows:-
Our cap is intended to be placed over or upon the chimneys or globes of
gas and other lights to prevent the smoke therefrom blackening the ceiling or
any thing which may be over them, while at the same time it allows passage
for the products of combustion to pass off from the chimneys or globes. We
are aware that glass caps have already been used which rest directly upon the
top of the globes, and are hollowed out all round their edge to allow of the
products of combustion passing off through the openings thus made. Being in
glass they are necessarily heavy, and are liable to break, and cut, and damage
whatever they may happen to fall upon.

page_text: Now, our Invention consists in the combination of a metal or other frame
fitted over or upon or formed in a piece with the glass chimney or globe,
with mica or talc. The mica or talc may be in the form of a flat disc, or of a
cone, or of any desired shape into which the mica or talc can be formed. By
our combination of a frame and a cap or cover of mica or of talc we secure
great lightness, avoid all danger of damage from any accident thereto, effec-
tually prevent the products of combustion, from blackening any thing which
may be over the light, and by taking care to allow sufficient space between the
surface of the tale and the upper edge of the chimney or globe, we provide
for the passing off of the products of combustion, which are, in effect, divided
into numerous currents, and driven out all round the edges of the mica or
talc cover.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Brooks. Pettit and Henry Fly Smith in the Great
Seal Patent Office on the 1st February 1858.
TO ALL, TO WHOM THESE PRESENTS SHALL COME, we, GEORGE
BROOKS PETTIT and HENRY. FLY SMITH, of Oxford: Street, in the County, of
Middlesex, Gas Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of August, in the year of our Lord One
thousand eight hundred and fifty-seven, in the twenty-first year of. Her. reign,
did, for Herself, Her heirs and successors, give and grant unto. us, the said
George Brooks Pettit and Henry Fly Smith, Her-special licence that we, the
said George Brooks Pettit and Henry Fly. Smith, our executors, administra-
tors, and assigns, or such others as we, the, said George Brooks Pettit and
Henry Fly Smith, our executors, administrators, and assigns, should. at any
time agree with, and no others, from time to time and at all times there-
after 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
CAP OR COVER FOR THE GLASSES OF GAS AND OTHER LIGHTS," upon the condition,
(amongst others) that, we, the said George Brooks Pettit and Henry Fly
Smith, or one of us, our executors or administrators, by an instrument in
writing under our, or their, or one of our or their hands and seals, 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
"

page_text: filed in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said George Brooks Pettit and Henry Fly
Smith, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof, reference being had to the
Drawings hereunto annexed, that is to say:-
Our cap is intended to be placed over or upon the chimneys or globes of
gas and other lights to prevent the smoke therefrom blackening the ceiling.
or anything which may be over them, while at the same time it allows passage
for the products of combustion to pass off from the chimneys or globes. We
are aware that glass caps have already been used, which rest directly upon the
top of the globes, and are hollowed out all round their edge to allow of the
products of combustion passing off through the openings thus made. Being
in glass they are necessarily heavy, and are liable to break, and cut, and
damage whatever they may happen to fall upon.
Now, our Invention consists in the combination of a metal or other frame,
fitted over or upon or formed in a piece with the glass chimney or globe,
with mica or tale. The mica or tale may be in the form of a flat disc, or of a
cone, or of any desired shape into which the mica or tale can be formed. By
our combination of a frame and a cap or cover of mica or of talc we secure
great lightness, avoid all danger of damage from any accident thereto, effec-
tually prevent the products of combustion from blackening anything which
may be over the light, and by taking care to allow sufficient space between
the surface of the talc and the upper edge of the chimney or globe, we provide
for the passing off of the products of combustion, which are in effect divided
into numerous currents, and driven out all round the edges of the mica or
talc cover.
We now proceed to describe the manner in which we carry our Invention-
into.effect, but we do not confine ourselves exclusively to the particular forms
herein-after described and represented in the annexed Drawings, but modify
the same according to circumstances.
We cut a disc of talc or mica the required size, according to the lamp glass-
or globe, or chimney or bucket lamp, so that the edge of the mica or tale may
project all round slightly over the lamp glass, globe, or chimney. The talc or
mica may also be of less diameter than the glass, but it should at least be
of the same diameter as the flame, and may be placed above, level with, or
within the glass. The edge of the talc or mica may be plain or otherwise.
Figure.1 is a view of a lamp glass and burner with one of our tale or mica

page_text: covers applied thereto; A is the cover, seen in plan at Figure 2; it is per-
forated about of an inch from its edge with a liole or slit a, to receive a slip
of wire, or strip of metal, or other suitable material, such, for example, as
asbestos, lava, and the like; a side view of one of these supports is shewn at
Figure 3. A second and similar hole or slit 6 is formed about an ½ of an
inch nearer the circumference than the slit a. A slip of metal or other
suitable material is cut the required length, (say about 4 inches,) and one end
is inserted through hole b, from the under side of the cover, is passed back
through hole a, and is secured by bending it back on to the talc or mica;
these bends will be understood on reference to Figure 3. The free end of the
slip of wire, or metal, or other suitable material is then curved outwards, in-
wards, and downwards, so as to form a shoulder to rest on the glass globe or
chimney, while the extremity c turned downwards prevents the cover slipping
off. We generally use three of these strips, but two, or more than three, may
be used. We sometimes also form the free extremity of the strip into a clip,
by recurving it back upon itself, and then bending it forward, so as to clip the
edge of the lamp glass, globe, or chimney, as shewn in the side view of one of
these strips at Figure 4; we can in this way use one strip only; or the
extremity of the strip or strips may be passed through a hole drilled in the
glass, and then fastened externally. We also, as in the case of argand
burners, fasten a rod or wire suitably to the centre of the burner, and at the
top of the rod or wire fasten the cover thereto, as shewn in the view Figure 5.
We also attach the frame for holding the tale or mica to the gas fitting itself,
or other convenient fixture, as shewn at Figure 6, where A is the metal frame
screwed or fastened at a to the gas fitting or other fixture, and formed at 6 so
as to clip or hold the talc or mica cover B. We also make the frame circular
to hold the talc or mica, which may be in the form of a plain dise or of a
conical form, as shewn at Figure 7. We also set pieces of tale or mica in a
metal frame of the form shewn in Figure 8. We also make a frame for the
cover, by having fixed to the lamp glass, globe, or chimney supports, either of
metal or of and on the glass itself, so that the cover may rest upon them, as
shewn at Figure 9; or projections may be formed on the inside of the glass
for the cover to rest upon. Care must be taken that a sufficient margin is
left between the cover and the glass to allow the gaseous products to pass off,
or the lamp glass, globe, or chimney has slits or perforations made at a proper
distance from the edge and round its circumference at certain intervals, and
the cover being so cut as to leave projections or slips, these slips are passed
through the perforations in the lamp glass, globe, or chimney.
It is obvious that modifications in the above enumerated modes of support

page_text: may be made, and we have detailed those which we have found to answer best.
The talc or mica cover itself is sometimes made in one, sometimes in two,
three, or more layers. We also place the layers either close together or
separated by an interval to allow an open space between them; the frame
being so adjusted as to carry the two or more layers. We also, in some cases,
fasten to the under side of the cover a layer of asbestos, or of asbestos woven or
twisted, so as to receive the heat from the burner.
In some cases we fit a mica or tale disc in a dished or other metal cup or
holder, the edges being turned over to hold the disc of talc or mica, strips are
connected to the edges of the cup or holder, and these rest upon the glass, or
the frame may be otherwise held.
And having now described the nature of our said Invention, and in what
manner the same may be performed, we declare that we claim the improved
cap or cover for the glasses of gas and other lights, formed by the combination
of a metal or other frame fitted over, or upon, or formed in a piece with the
glass chimney or globe with mica or talc, in manner and for the purposes
herein-before described.
In witness whereof, we, the said George Brooks Pettit and Henry Fly
Smith, have hereunto set our hands and seals, this First day of
February, One thousand eight hundred and fifty-eight.
RADAR DDAAIZA
CEORGE BROOKS
HENRY FLY SMITH.
D.S.
(L.S.)