IMPROVEMENTS IN APPARATUS FOR PRODUCING LIGHT BY ELECTRICITY
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Benjamin Pryor Stockman at the
Office of the Commissioners of Patents on the 26th October 1878.
BENJAMIN PRYOR STOCKMAN, of Poet's Corner, Westminster, in the County of
Middlesex, Civil Engineer. "IMPROVEMENTS IN APPARATUS FOR PRODUCING LIGHT
BY ELECTRICITY."
My Invention relates to improvements in apparatus for the production of the
electric light.
The object of the said Invention is the maintaining of the carbon points, carbon
candles, or "carbons" in the proper position for combustion.
I keep the said carbon points in constant adjustment to the distance apart
required for the electric or volatic arc by flotation, that is to say, by a float or
floating or buoyant support in a liquid. For this purpose I use a cylindrical or
other vessel containing the liquid, and in this liquid I place a piston or float which
carries one of the carbons herein-after termed the lower carbon.
I may use water or any other suitable liquid, but in the following description I
prefer more particularly to the employment of mercury for floating the lower carbon
in my apparatus.
The upper carbon after being placed in its holder is a fixture, that is to say, it is
not made to descend from its holder to compensate for its loss by combustion as in
the ordinary electric lamp, but the lower carbon moves upwards by its flotation or
yielding support in the mercury contained in the cylinder.
I place within the said cylinder an inner vessel, which may be called an inverted
cylinder, sliding telescopically in the outer cylinder, and through the neck of this
inverted cylinder the piston or piston rod holding the lower carbon passes. By a
small rack and pinion, or screw and nut, or other suitable means I raise or lower
the inner inverted cylinder as required.
By making this inner cylinder descend into the mercury I cause the piston or
float to rise until the lower carbon comes in contact with the upper carbon, and
when an electric current is thus established I raise the inner cylinder until the
light is obtained; from this moment the loss of weight of the carbon causes a
diminution of the displacement of the mercury column which it carries. The area
077

page_text: of the surface of the mercury is so regulated that the decrease of vertical displace-
-ment exactly equals the vertical loss or decrease of the carbons.
I sometimes use an automatic arrangement-to-lower and raise the inverted
cylinder, that is to say, I use an electro-magnet which is actuated by the current
passing through the carbon, and in case of any derangement of the carbons would
cause the inverted-cylinder_to_descend and bring the two carbons properly into
contact again.
To obviate inconvenience arising from change of position of the light due to the
reduction of the upper carbon I use in some cases a gravitating arrangement to
lower the whole apparatus at intervals or continuously.
The lower carbon is inserted in a holder or socket-which is a part of or is attached
to the piston or piston rod, and the upper carbon is held fast in an immovable
holder.
I apply my Invention to parallel carbons, that is to say, I use a pair of carbons
parallel with each other, floating in a vertical position in the mercury or other
liquid, or placed at an equal angle with a vertical line between them, in which case
the cylinders wherein they float will be in the same line and at the same angle.
By this arrangement the said carbons are kept to a constant level during their
combustion. In some instances I may apply my Invention to carbons supported
on levers or arms, each of which is mounted on a fulcrum. The point of contact or
combustion is at one end of these levers, whose other end is provided with a float
supported in the mercury or other fluid which acts to compensate for the diminu-
tion of the carbons by combustion, as above described.