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UNITED STATES PATENT OFFICE.
WILLIAM LAWRENCE, OF WALLINGFORD, CONNECTICUT. COACH-LAMP.
Specification of Letters Patent No. 683, dated April 7, 1838.
To all whom it may concern:
Be it known that I, William Lawrence, of Wallingford, in the
county of New Haven and State of Connecticut, have invented a new
and useful Improvement in the Construction of Coach-Lamps; and
that the following is a full and exact description thereof,
reference being had to the annexed drawings of the same, making
part of this specification.
To enable others skilled in the art to make and use my invention
I will more particularly describe its construction and operation.
Instead of the square or oblong shape of coach lamps in common
use, I make the frame or body A, Figure 1, cylindrical and for
stage coaches about 7 inches in diameter and about 6 inches long;
for other carriages it may be proportionately less. It may be
made of tin, or any other suitable metallic plates, and painted
or japanned. This cylinder is supported horizontally, the front
end is closed by a pane or plate of clear glass B, the rear is
closed by a door C hung on a hinge, and on the inside of that
door I attach a highly polished reflector D the full size of the
cylinder curving in the shape of a tea saucer. For this reflector
I prefer a highly polished silver plate.
On the bottom of this cylinder is a socket E about 4 inches long
and 1— inches in diameter, closed at the bottom, but opening into
the body of the cylinder. This socket is for the double purpose
of attaching it to the coach and also to receive and hold in
place the oil lamp F, and directly over the socket is a chimney G
in common form; and for the purpose of giving air to the lamp
uninfluenced by the motion of the carriage or the current
without, I raise a floor H Figs. 1 and 2 about half an inch high,
around the mouth of the socket at the bottom of the cylinder.
This floor is pierced with air holes I around the edges and the
air chamber below this floor is supplied by air holes J in the
outward shell of the cylinder in front and in rear of the socket,
these holes in the floor and in the shell are not opposite each
other and of course the light is not sensibly affected by the
These lamps may be made larger or smaller than the size herein
specified as occasion may require. They may also be made with
suitable alterations, to stand perpendicularly, or on one end,
but I prefer the horizontal position. In either case they are
attached to the coach in the usual manner.
The inner lamp F for oil consists of a circular hollow vessel F
about 2— inches diameter and one inch and a quarter deep closed
at the bottom and top excepting an * aperture in the center of
the bottom for a : long hollow shank L Fig. 3 closed at its lower
end for containing oil and an aperture in the center of the top
for a screw M through which passes a conical or cylindrical tube
N Fig. 3 for the wick and an orifice through which the oil is
admitted closed by a stopper O. The bottom of the lamp where it
unites with the shank forms a shoulder P which rests upon the
perforated plate of the body. The exterior of the shank of the
oil lamp is shaped to fit the socket of the case into which it is
inserted. The conical tube N for the wick extends nearly to the
bottom of the oil shank L.
The advantages of this improvement are that the light of this
lamp is more brilliant than any now in use for a similar purpose,
and is not liable to be extinguished from the agitation of the
oil in the lamp (caused by the motion of the carriage) drawing
down the wick from the tube, or at other times quenching the
flame by the motion of the oil from the same cause the small wick
tube in the center of the lamp protecting the wick from the
motion of the oil (however violent) and preventing the
extinguishment of the light and causing it to burn much longer
than any other lamp on account of the depth of the shank of the
lamp into which the wick tube extends—the oil continuing to rise
in this tube until nearly exhausted in the shank, not only from
the draft of the lamp, but from capillary attraction—or the
attraction of the periphery of the concave surface of the small
tube to which the upper surface of the oil is contiguous and
adheres; besides the light is not liable to be influenced from
external currents of air, owing to the before described
arrangement of the apertures in the bottom of the case and in the
segment floor above it.
The invention claimed and desired to be secured by Letters Patent
1. The shank at the bottom of the lamp into which descends a
small tube containing the wick immersed in the oil as before
described and for the purpose therein set forth—said hollow shank
being made to fit a socket in the shank of the outer case.
2. Also the raised floor above the bottom of the outer case and
the manner in which they are perforated as before described.
Witnesses: Wm. P. Elliot, J. B. Wood.