IMPROVE- MENTS IN ELECTRIC LAMPS
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by the said Sidney Waters at the Office
of the Commissioners of Patents on the 27th March 1882.
SIDNEY WATERS of Ladbroke Square in the County of Middlesex " IMPROVE-
MENTS IN ELECTRIC LAMPS "
The object of my Invention is to increase the illuminating power of electric
lamps, more particularly of incandescent lamps, and at the same time give a more
pleasing effect.
My Invention consists in forming one half more or less of the globe or flask of
the lamp into a concave mirror and this may be done by coating the glass externally
with an amalgam formed from tin foil and mercury or by a deposit of silver
produced by chemical action or deposition upon the exterior of the flask. The
particular portion of the globe which is formed into, a mirror will depend upon the
position in which the lamp is intended to be used; for example if the lamp is to
be placed against a wall the part or half of the globe nearest the wall will be
formed into a mirror; if the lamp is to be overhead the upper portion will be
converted into a mirror.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Sidney Waters in the Great Seal Patent Office on the
26th September 1882.
SIDNEY WATERS of Ladbroke Square in the County of Middlesex
MENTS IN ELECTRIC LAMPS
"IMPROVE
My Invention has reference to increasing the illuminating power of incandescent
electric lamps, and at the same time giving a more pleasing effect, by forming one
half more or less of the globe or flask of the lamp into a concave mirror, this
object being effected by coating the glass externally with silver by chemical action
or deposition.
According to my Invention I mix tartrate of silver (which may be obtained in
the ordinary manner) with an amount of ammonia which is almost but not quite
sufficient to dissolve it but will leave it in a milky state. Into this solution or
liquor I immerse so much of the lamp globe or flask as it is desired to coat with
silver, the globe or flask having been previously fitted with its carbon filament,
exhausted and. sealed; I then heat the solution by sending an electric current
through the lamp and the silver is thus caused to be deposited upon the exterior
of the immersed portion of the globe. To prevent as much as possible the deposit
of silver upon the surface of the vessel containing the solution, I sometimes cool it
by any suitable means while the electric current is heating the lamp itself.
The particular portion of the globe which is formed into a mirror will depend
upon the position in which the lamp is intended to be used; for example if the
lamp is to be placed against a wall the part or half of the globe nearest the wall
will be formed into a mirror; if the lamp is to be used overhead the upper portion
will be converted into a mirror. -
In order to prevent a dark shadow being thrown on the wall behind, or on the
ceiling above the lamp, I make the deposit of silver sufficiently thin to be partly
or semi-diaphanous so as not to entirely reflect the light.
In witness whereof I the said Sidney Waters have hereunto set my hand
and seal this 19th day of September One thousand eight hundred and
"eighty two.