CERTAIN IMPROVEMENTS IN OR ADDITIONAL TO LAMPS, AND FOR RENDERING THE ILLUMINATION MORE SOFT AND AGREEABLE TO THE EYE
Year: 1811

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PETER
DURAND, of Hoxton Square, in the County of Middlesex, Merchants, 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 Third day of August, in the
fifty-first year of His reign, give and grant unto me, the said Peter Durand,
his exors, adñiors, and assigns, His especial licence, full power, sole privilege
and authority, that I, the said Peter Durand, my exors, adiñors, and assigns,.
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, the Invention communicated
to me by a certain Foreigner of "CERTAIN IMPROVEMENTS IN OR ADDITIONAL TO
LAMPS, AND FOR RENDERING THE ILLUMINATION MORE SOFT AND AGREEABLE TO THE
EYE;" in which said Letters Patent there is contained a proviso that if I,
the said Peter Durand, shall not particularly describe and ascertain 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 six calendar
months next and immediately after the date of the said recited Letters
Patent, that then the said Letters Patent, and all liberties and advantages
whatsoever thereby granted, shall utterly cease, determine, and become void,
as in and by the same, relation being thereunto had, may more fully and at
large appear.
NOW KNOW YE, that I, the said Peter Durand, in compliance with the
said proviso, do hereby declare that the nature of the said Invention, and

page_text: the manner in which the same is to be performed, are described and ascertained
as follows (that is to say) -
In the Drawings hereunto annexed Figure 1 and Figure 2 represent two
of the lamps, consisting, as to the body of the same, of four chambers or
reservoirs, in or by means of which the oil is elevated by the action of com-
pressed air; and the said description of lamps being well known by the name
of French lamps, it will be easy for any workman to distinguish the parts or
In
variations thereof wherein my improvements or additions so consist.
Fig. 1 the chamber or reservoir A contains oil intended to rise through the
tube H, G, to maintain and support the flame, and the reservoir B contains
oil, which, by flowing down through the pipe N, O, into the chamber or
reservoir C, compresses the air contained in the said last-mentioned chamber.
And D is a chamber or reservoir for the sole purpose of receiving thro' the
the pipe R, S, such portions of oil as may be spilled in filling the lamps, or
may at any time run-over the top of the tube H, G. is a small valve or
stopper not before used in these lamps, and consisting of a plate metal or other
fit material capable of being raised or depressed by the stem A, G, which
passes through the piece C by an opening kept air-tight. The use of the said
valve is to close the, tube I, I, when there may be occasion, as herein-after
shewn, to reverse the lamp, and by such closure the oil contained in the
chamber C is prevented from flowing into A. It is also proper to keep the
said valve shut when the lamp is not in use, in order to prevent the air from
passing from C into A. And I do farther declare that a cock or any other
well-known means of shutting and opening the communication thro' K, I,
may be used and applied instead of the said valve. E is an opening through
which the lamp is, supplied with oil, and the same must be provided with a
screw stopper, well fitted or faced with leather, or the closure must be effected
by any other convenient means, so as to be accurately air tight. d, e, f, g,
represents a cylinder of tin or other metal having a close bottom at e, f,, from
which rises a small cylinder p, intended to receive the lower extremity of the
tube O, N. The said cylinder surrounds and contains the lamp. itself, of
which the chamber C has no other bottom than that of the cylinder e, f, so
that by taking the lamp out of it becomes easy to examine and clean the
several
parts thereof when requisite. The bottom of the said cylinder may be
faced within with a piece or rim of leather or felt, or other similar substances,
against which the lower edge of the sides of the chamber C may be pressed,
so as to close the same, or otherwise the closure may be more accurately and
strongly made, by screwing the lamp into the cylinder, or by other usual
meaus; but altho' it is convenient that the said lower chamber should, be

page_text: F
closed as aforesaid, yet it is not indispensably necessary, because the effect of
the lamp would take place completely when the said cylinder should be put
on, in case the said closure where not made. The method of charging and
using the said lamp is as follows: Let the valve & be opened, and oil poured'
in thro' e, and the same will fill the chamber A, and force the air contained'
therein thro" I; K, into C, and thence by communication a like portion of "air"
will pass thro' O, N, into B, and thro' M, L, into the open air. Let more oil
continue to be poured in, and the chamber C will become full, and the oil will
ascend thro' O, N, into the chamber B until the lower extremity of the tube
M, L, becoming covered, will prevent any more air from passing up M, L
and because the chamber B is closed in "every part except at N and M, tlic
air included therein will become condensed by the pressure of the oil, and will
resist that pressure, and cause oil to arise in M, L, to L, that is to say, on a
level with the oil at E, and in the open tube H, G, intended to receive the
burner. Let the valve B and the orifice E be now closed, and the whole lamp
reversed, and oil will run from the chamber C into the chamber B thro O, N,
and the air from the chamber 'B'will return to the chamber C through the
same passage; which' for that purpose must be made rather large, or else be
provided with an interior tube, 'dotted at p:) "As soon as "the "effect has taken
place let the lamp be restored to its erect position; and the valve be opened,
and the oil will again pass from B to C, but will in the first place fill the
small cylinder P, and tliereby prevent any more air from passing up O, N,
and the farther descent of oil from B will condense the air in C, and cause
the same to exert its pressure thro" K, I, upon the oil in A, so that the oil
which, before the reversing of the lamp, stood in G, I, at the level of Es
will now stand 'much higher, and will constantly supply the burner when
placed at H.
T
Figure 2 represents a lamp in which molasses or some other fluid heavier
than oil is used to compress the air. The difference between this lampant
Fig. 1 are (1) the lower reservoir C has rather more than double the capacity.
of the reservoir B; (2) the air pipe I, 'K, descends to the middle of the
reservoir C, and sliould be placed as nearly as convenient with its lower orifice
at an equal distance from the sides; (3), the air tube I, K, rises a little above
the level of the orifice E, so as to prevent any oil from passing down into C.
In this lamp the chamber B may be supplied with molasses in a measured
quantity, not sufficient to reach the bottom of the air pipe K) thro' L and the
chamber A.filled with oil thro' E, or otherwise the molasses may be introduced
at the bottom e, f, by taking off the surrounding cylinder; and in-lamps of the
construction; herein last described, oil, or any other fluid not changing or
changeable by oil, may be substituted instead of the dense liquor before

page_text: mentioned, provided the relative lengths of the tubes N, O, and H, G, and the
sizes of the chambers B and C, be duly regulated according to the elementary
principles of hydrostatics, explained in all the books, and dependant upon
the specific gravity of the fluid made use of as aforesaid. c, c, c, represents
a small dish, which may be affixed beneath K, to prevent the possibility of any
oil falling against or entering the aperture of the air tube during the act of
reversing.
Fig. 3 represents the construction of an aparatus for holding a simple
wick capable of adjustment in length, and applicable to the above or any other
description of lamps. A, A, is the supporter of the glass shade, resting, as
usual, upon the tube a, b, c, d, which supplies the oil, and communicating with
an inner tube n, o, p, q, in which are two longitudinal slits, and which can
be made to turn round by turning the piece A, A. K is a fixed nut in which
the screw h being inserted can, by being turned, move up and down. m is
an head affixed to the screw, and moveable by the turning of the tube n, o, p, q,
with which tube it has communication by small projection into the slit, as shewn
in Plate at Fig. 4. e, g, is the wick-holder, consisting of several pieces of
elastic metal, between which the wick is compressed when drawn into the
tube a b, c, d; and Fig. 5 shews the same sperately.
Fig. 6 represents a lamp (intended more particularly for work) into which
the circular reservoir with permanent level is applied as an improvement.
a, b, c, d, is the shade of tin or other metal, and round the same is applied the
circular vessel intended to contain the oil; i, the orifice for pouring in oil;
K, I, a tube thro' which the external air enters the reservoir to supply the
place of the oil as it is consumed, and keeps the level constant with its
lower orifice 7, in the usual valve or other means of closing the communication
of oil to the lamp when required thro' N, O. The lamp itself is capable of
any kind of wick, and is shewn as placed in an open-mouthed support or
candlestick to receive any oil that may accidently be spilled or overflow.
And, lastly, I do render the illumination more soft and agreeable to the eye
by using a shade or reflector made of porcelain, or of the other known com-
pounds of earth, alkaline, or metallic bodies in a partly vitrified state, or of
glass rendered semi-transparent by exposure to heat, till the same hath
become converted into the state in which it is known by the name of
Reaumur's porcelain.
In witness whereof, I, the said Peter Durand, have hereunto set my
hand and seal, this Third day of February, in the year of our Lord
One thousand eight hundred and twelve.
PETER DURAND. (L.S.)

page_text: AND BE IT REMEMBERED, that on the Third day of February, in the
year of our Lord 1812, the aforesaid Peter Durand came before our said
Lord the King in His Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained and specified, in form above
written. And also the Specification aforesaid was stampt according to the
tenor of the Statute made for that purpose.
Inrolled the Third day of February, in the year of our Lord One thousand
eight hundred and twelve