CERTAIN IMPROVEMENTS ON SAFETY LAMPS
Year: 1827

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
BONNER, of Monkwearmouth Shore, in the County of Durham, Merchant, do
send greeting.
WHEREAS His most Excellent Majesty King George the Fourth, by His
Letters Patent under the Great Seal of the United Kingdom of Great Britain
and Ireland, bearing date at Westminster, the Fourth day of December now
last past, did give and grant unto me, the said Thomas Bonner, my executors,
administrators, and assigns, His special license, full power and authority, that
I, the said Thomas Bonner, should, during the term of years therein expressed,
and lawfully might make, use, exercise, and vend, within England, Wales,
and the Town of Berwick-upon-Tweed, and also within all His. Majesty's
Colonies and Plantations abroad, my Invention of "CERTAIN IMPROVEMENTS ON
SAFETY LAMPS;" in which said Letters Patent there is. contained a proviso,
obliging me, the said Thomas Bonner, by an instrument in writing under
my hand and seal, particularly 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
months next and immediately after the date of the said recited. Letters Patent,
as in and by the same, reference being thereunto had, may more fully and
at large appear.
NOW KNOW, YE, that in compliance with, the said proviso, I, the said
Thomas Bonner, do hereby declare that my said improvements on safety lamps
are fully described and ascertained as follows, that is to say :-

page_text: My improvements consist, first, of a means of increasing the light of the
lamp; and, secondly, of methods for extinguishing the flame. These improve
ments are fully explained and ascertained by the accompanying Drawings, and
the following description thereof, that is to say :-
Fig. 1 is a section of the lamp exhibiting the improvements; A & B are
plans of the top of the lamp, showing two covers of peculiar form for extin-
guishing the light. In plan A the covers are exhibited open, and in plan B
shut. My first improvement for increasing the light of the lamp is effected as
follows: Instead of introducing a wick in the centre of the lamp as is at pre-
sent practised, I introduce several small wicks round a centre tube, as shewn
at a, Fig. 1, and Plan A, by which means, by lighting one or more wicks, as
occasion may require, I obtain either little or much light. These wick tubes
are fixed in a metal ring, whose inner diameter is rather larger than the outer
diameter of the fixed open tube in the center of the lamp, and the outer dia-
meter of the ring is rather less than the diameter of the opening for the light
on the top of the lamp, so that this ring with the wick tubes fixed in it slips
easily in and goes round the centre tube, the inner edge of the ring resting
upon a narrow ledge left on the centre tube (shewn at 6, Fig. 1) to support it,
or the outer edge of it rests on a ledge left round the opening for the light,
as shewn at c, and as the ring is thereby at perfect liberty to revolve, the wicks
are carried round by the trimming iron. The ring may either be level with
the top of the lamp or a little below it, but those parts of the wick tubes having
the slits for trimming must be above the ring, and a slit made on each side of
them, but not opposite each other in the same tube. My methods for extin-
guishing the light are as follows:-First, d, d, Fig. 1, and Plans A and B,
shew two covers of peculiar form for extinguishing the flame while unscrewing
the gauze top, which is enlarged in diameter at bottom, as shewn at f, f, Fig. 1,
to allow room for these covers. The light by means of these covers is thus
prevented from being improperly exposed. The covers are formed of two
pieces of thin metal placed upon the upper side of the lamp, upon studs or
otherwise, so as to traverse and pivot on the pin or screw O, Fig. 1, and o, o,
Plans A and B. The covers are carried over the light, so as to extinguish it
by any mechanical means that may be preferred, but I adopt one or more
catches affixed on the screw ring, as shewn at e, Fig. 1, and Plans A and B.
Secondly, I extinguish the light by an extinguisher suspended, as shewn at g,
at the top of the gauze cylinder, by a combustible substance, such as a piece
or slip of wood or paper, or otherwise as afterwards described, which extin-
guisher falls upon the light when the combustible substance is either burnt or
broken by pressing upon the driver i. This extinguisher is formed of a thick

page_text: circular piece of metal of the same diameter as the interior of the gauze cylin-
der, or nearly so. It is shewn at g, Fig. 1, and separately at Drawing C. It
is made with two grooves to slide on two wires h, h, Fig. 1, to guide it on its
assent and descent, which wires are screwed at the upper end to the brass top p
of the cylinder, and at the lower end to two of the outer wires. This extin-
guisher may also be suspended by a pin k, to be inserted at 1 or m, or it may be
any otherwise suspended. In Fig. 1, n shews a piece of metal or wire to be
used as a trimming iron, to which, however, I make no claim.
In witness whereof, I, the said Thomas Bonner, have hereunto set my
hand and seal, this Fourth day of June, One thousand eight hundred