IMPROVEMENT England, Wales, and the Town of Ber-upon-Ted, my IN THE CONSTRUCTION OF LAMPS
Year: 1808

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, СпARLES
SEWARD, of Lancaster, in the County of Lancaster, Block Tin Manufacturer,
do send greeting.
WHEREAS His most Excellent Majesty King George the Third, by His
Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-sixth day of
November now last past, did give and grant unto me, the said Charles
Seward, my executors, administrators, and assigns, His special licence; full
power, sole priviledge and authority, that I, the said Charles Seward, my
executors, administrators, and assigns, during the term of years therein
expressed, should and lawfully might make, use, exercise, and vend, within
"IMPROVEMENT
England, Wales, and the Town of Berwick-upon-Tweed, my
IN THE CONSTRUCTION OF LAMPS;" in which Letters Patent there is contained
a proviso obliging me, the said Charles Seward, under my hand and seal, to
cause a particular description of the nature of my said Invention, and in
what manner the same is to be performed, to be enrolled in His Majesty's
High Court of Chancery within one calendar month next and immediately
after the date of the said recited Letters Patent, as in and by the same
(relation being thereunto had) may more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Seward; do hereby declare that my said Invention is described in
manner following (that is to say) :-

page_text: lamp, and then point out those improvements which I call my own, observing
that I would claim a patent for each of these improvements separately, as well
as for the improved lamp itself. This combination of improvements in the
construction of lamps may remain the same, and yet the form of the lamps be
infinitely varied. The following is a description of the most useful and common
form of those lamps.
DESCRIPTION OF THE LAMP.
A is the lamp or reservoir of the oil, the shape of which is immaterial, so
that it may be made very shallow, or at least as shallow as it conveniently
may, in order that the oil be always near the flame, and have as little as
possible to ascend up the wick. It is also of some importance that the body
of the lamp be made no larger than to contain a sufficient quantity of oil for
each time of burning. b, b, is the flat tube to contain the wick. This tube
is made so long as to reach quite to the bottom of the lamp; and in order to
give room to the wick a little of one side of the wick tube is cut away or
doubled up at the bottom, as at Fig. 1, which is a section of the lamp, but
represents the wick tube entire. The advantages attending this construction
of the tube are, that the oil is warmed and kept from coagulating, especially
that part of it which immediately surrounds the wick and is in contact with
the tube, which in consequence of its conducting power soon becomes warm
throughout its whole length. Also the wick in a tube of this construction is
not liable to slide down and extinguish the light; a defect frequently met with
in lamps having tubes of the common construction. The wick tube is soldered
or otherwise fixed into a small round plate of tin, brass, or other suitable metal,
the edge of which rests upon a shoulder on the inside of the brass screw d, d.
The plate and tube are held in their situation by means of a male screw c, e, as
in Miles's lamps. Fig. 2 represents the above plate, in which bis the tube,
and a small hole for the admission of air. B is the chimney or lamp glass.
The shape of it is distinctly seen in the Figure, and therefore requires no
description. It is placed about a quarter of an inch above the top of the
wick tube, leaving a space from the bottom of the chimney to the top of the
brass screw of about half an inch, for the admission of air, instead of having
air tubes, as in Argand's lamps. But the proper height of the glass chimney
above the lamp must be determined by experiment, for it varies with the
size of the wick tube and the size and even the form of the lamp. The
chimney's support consists of a pretty strong wire g, g, the lower end of which
is soldered or otherwise firmly fixed into the body of the lamp at h, and to the

page_text: other at i is soldered or otherwise fastened a hoop of tin or any other metal
capable of springing or opening so as to embrace the lamp glass. The lower
end of the chimney rests upon a support k, firmly and immoveably fixed to the
wire g, g. In order to keep the lamp glass steady, this support should at least
be a quarter of an inch wide. The edge of it is only seen in the Figure. These
chimneys are not liable to be broken by the heat of the flame; they are also
much stronger than cylindrical glasses, and have a handsome appearance,
especially when the globular part is ground or roughened.
DIRECTIONS FOR TRIMMING AND USING THE LAMPS.
Unscrew the top, and charge the tube with a piece of wick leaving nearly
a quarter of an inch of the wick above and about one inch below the tube.
The higher the wick is the better, so that the lamp does not smoke. It is
proper to observe, in regard to those lamps with chimneys, that they are
more liable to smoke immediately after placing the chimney than when it
I has been on a few minutes and got heated by the flame. The wick is easily
introduced into the tube by means of a strip of tin which is sent with the
lamp. Having charged the tube, replace it in the lamp, taking care to put
the end of the wick so that it may lay at the bottom of the lamp on the
side of the tube, which is cut away in order to make room for it. Having
filled the lamp, screw the top tight down, to prevent the oil from spilling. The
proper oils for these and all other lamps are those which are clear and pale
colour. The dark coloured oils generally contain a considerable quantity of
impure matter, which, not being inflammable, accumulates on the wick,' and
remains there in the form of a crust.. Therefore, if whale oil be used, it must
be the cold drawn, which may be distinguished by. its transparency and pale
colour. Whenever bad oil has been used, on changing it the wick that has
been used with it must also be changed. If the lamp be trimmed in a morning,
or some time before using, the dirt and other extraneous matter contained in
the oil will subside.. A fresh piece of wick must be put in every two or three
nights, and the burnt part cut off every night; and though the whole of the
oil should not be consumed in one burning, yet the lamp ought to be filled up
every time it is used. The oil when not in use should be well corked up, and
the wick and every thing belonging to the lamp kept as clean as possible..
The roughened glass chimneys are best cleaned with soap and water, and the
others may be rubbed with a piece of wash leather. I shall now point out
those improvements which I claim separately as my own.
First, the additional length of the wick tube, or its reaching to the bottom
of the lamn