IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS
Year: 1882

page_text: LETTERS PATENT to Frank Wright and Matthew William Wallbank Mackie,
both of No. 80, Gray's Inn Road, in the County of Middlesex, for an invention
PROVISIONAL SPECIFICATION left by the said Frank Wright and Matthew
William Wallbank Mackie at the Office of the Commissioners of Patents on
the 3rd March 1882.
FRANK WRIGHT and MATTHEW WILLIAM WALLBANK MACKIE both of No. 80
Gray's Inn Road in the County of Middlesex "IMPROVEMENTS IN INCANDESCENT
ELECTRIC LAMPS
"
Our invention relates to the construction of the bulbs of electric lamps and
means of attaching the fibres to their conductors in a simple and durable manner.
In forming the bulb with the conducting wires we proceed as follows. We fix
on a tube by means of spun glass the two conducting wires which have the carbon
fibre attached to them in the manner which we will hereafter describe or in any
known manner.
We insert the tube with the wires on it into the tubular throat
of the bulb and then by heating the tubular throat we cause it to collapse on the
tube and wires closing them in hermetically. The end of the inner tube is drawn
out to a small bore and forms the passage for extracting air from the bulb. By
heating the throat of the bulb and pushing the inner tube in, the throat is caused
to fold inwards on itself so that the point of the inner tube is in such a position
as to be protected by the external throat of the bulb projecting beyond it. For
attaching the fibre to its conductors we first thicken the ends of the fibre by
coating them with syrup and then carbonising the sugar of the syrup by
application of sulphuric acid. We insert the thickened ends of the fibre into
tubular pieces of platinum formed by bending the ends of platinum strips into
tubular form, and we tighten the platinum on the fibre by a washer of steatite
enclosing it.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Frank Wright and Matthew William Wallbank Mackie in the
Great Seal Patent Office on the 31st August 1882.
"
FRANK WRIGHT and MATTHEW WILLIAM WALLBANK MACKIE both of No. 80
Gray's Inn Road in the County of Middlesex IMPROVEMENTS IN INCANDESCENT
ELECTRIC LAMPS."
Our invention relates to the construction of the bulbs of electric lamps and
means of attaching the fibres to their conductors in a simple and durable manner.
In forming the bulb with the conducting wires we proceed as follows. We fix
on a tube by means of spun glass the two conducting wires which have the carbon
fibre attached to them in the manner which we will hereafter describe or in any
known manner. We insert the tube with the wires on it into the tubular throat
of the bulb and then by heating the tubular throat we cause it to collapse on the
tube and wires closing them in hermetically. The end of the inner tube is drawn
out to a small bore and forms the passage for extracting air from the bulb. By
heating the throat of the bulb and pushing the inner tube in, the throat is caused
to fold inwards on itself so that the point of the inner tube is in such a position as
to be protected by the external throat of the bulb projecting beyond it. For
attaching the fibre to its conductors we first thicken the ends of the fibre by coating
them with syrup and then carbonising the sugar of the syrup by application of
sulphuric acid. We insert the thickened ends of the fibre into tubular pieces of
platinum formed by bending the ends of platinum strips into tubular form, and we
tighten the platinum on the fibre by a washer of steatite enclosing it.

page_text: Second. Securing the carbon fibre to the conductors by forming the ends of the
conductor tubular and after inserting the ends of the fibre therein securing the
same by a ring of steatite substantially as herein described.
In witness whereof I the said Frank Wright have hereunto set my hand
and seal this thirty-first day of August in the year of Our Lord One
thousand eight hundred and eighty two.
FRANK WRIGHT. (L.S.)