IMPROVEMENTS IN THE MANUFACTURE OF ELECTRIC BRIDGES FOR LAMPS."
Year: 1881

page_text: LETTERS PATENT to St. George Lane Fox, of Queen Anne's Gate, in the City
of Westminster, for an Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF ELECTRIC BRIDGES FOR LAMPS."
PROVISIONAL SPECIFICATION left by the said St. George Lane Fox at the;
Office of the Commissioners of Patents on the 18th July 1881.
ST. GEORGE LANE Fox, of Queen Anne's Gate, in the City of Westminster.
"IMPROVEMENTS IN THE MANUFACTURE OF ELECTRIC BRIDGES FOR LAMPS."
My Invention relates to the manufacture of electric bridges from certain grasses
or fibres, and more particularly from the grass or fibre known as French whisk.
Hitherto attempts to manufacture bridges from this fibre have failed owing to
the baked fibre flying to pieces on the application of the electric current.
I manufacture bridges from this fibre and other like grasses or fibres as
follows: I first boil the fibres in a strong solution of caustic soda or potash. I
then scrape or clear off the outer skin, and afterwards boil the fibres in water until
all trace of soda or potash is removed.
I then stretch the fibres on a block of
carbon or other suitable material buried in plumbago, or hermetically sealed in a
crucible, and I raise them to a white heat in the usual inanner.
Then, after carbonizing if desired, the fibres are ready for mounting as electric
bridges in lamps.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said St. George Lane Fox in the Great Seal Patent Office on the 17th
January 1882.
ST. GEORGE LANE Fox, of Queen Anne's Gate, in the City of Westminster.
"IMPROVEMENTS IN THE MANUFACTURE OF ELECTRIC BRIDGES FOR LAMPS."*
My Invention relates to the manufacture of electric bridges from certain grasses
or fibres, and more particularly from the roots of the Italian grass (Andropogon
Ischomum, or Chrysopogon Gryllus), this fibre being known as French whisk.
Hitherto attempts to manufacture bridges from this fibre have failed owing to the
baked fibre flying to pieces on the application of the electric current.
I manufacture bridges from this fibre and other like fibres or grasses as
follows-I first boil the fibre in a solution of caustic soda or potash. The action
of the caustic alkali must not be continued too long, as I find the fibre is liable to
become rotted, and for this reason I prefer to use a solution which is not too strong,
say, a solution containing 5 per cent. of caustic alkali. I then scrape or clear
off the outer skin, and afterwards boil the fibres in water. In order to straigthen
the fibre I stretch it after its removal from the solution and while it is still
damp. For this purpose I may fix each end in a frame or clamp, or fix one
end in a clamp and attach a weight to the other end; or I may attach a weight to
each end and hang it by its middle over a cylindrical horizontal bar until dry.
I then bind the fibres thus straightened on a block of carbon or other suitable
material, buried in plumbago or hermetically sealed in a crucible, and I raise them
to a white heat in the usual manner.
Then after carbonizing if desired the fibres are ready for mounting as electric
bridges in lamps.
In witness whereof, I, the said St. George Lane Fox, have hereunto set my
hand and seal, this Seventeenth day of January, One thousand eight hundred
and eighty two.¯¯
ST. G. LANE FOX. (L.S.)