IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS, AND IN GLASSES THEREFOR to
Year: 1884

page_text: I, GEORGE HOOKHAM of 7 & 8 New Bartholomew Street Birmingham Manu-
facturer do hereby declare the nature of my invention for IMPROVEMENTS IN
INCANDESCENT ELECTRIC LAMPS, AND IN GLASSES THEREFOR to be as follows:-
The object of this invention is to obtain diffusion of the light from an inçán-
descent lamp with less loss than results from the use of ground or opal glass.
I require for my purpose an incandescent lamp in which the carbon wick consists
either of a single straight filament, or, if the filament is bent into a loop, its two
sides should be parallel and as close together as possible; the object in each case
being to obtain a long narrow and straight line as the source of light. The bulb'in
which such filament is enclosed should itself by preference have a form more or less
cylindrical as compared with the spherical or pear-shaped forms at present in use.
With such a lamp I combine a lamp-glass which slides over the lamp and has either
convex ribs or concave grooves on one or both sides of the glass (but not convex on
one side and concave on the other) such grooves or ribs running parallel to the long
and narrow filament. It is clear that the effect of the lamp-glass will be to spread
out the narrow intense line of light into a sheet of light which is less intens and
therefore less trying to the eye, but in which the total amount of light will be
about the same.
Supposing the inside surface of the lamp-glass to be from one inch to one and a
half inches distance from the carbon, the best effect will be produced when the ribs
or grooves bave a curvature due to a radius not exceeding one tenth of an inch.
The ribs or grooves may be either cut or moulded.
I prefer the shape of the glass to be cylindrical, but it may consist of a number
of flat sides forming a prism: In all cases I combine the long and narrow wick or
filament with ribs or grooves in the glass running parallel to it.

page_text: COMPLETE SPECIFICATION,
I, GEORGE HOOKHAM of 7 and 8 New Bartholomew Street Birmingham Manu-
facturer, do hereby declare the nature of said invention for "IMPROVEMENTS IN
INCANDESCENT ELECTRIC LAMPS AND IN GLASSES THEREFOR," and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
The object of this invention is to obtain diffusion of the light from an incan-
descent lamp with less loss than results from the use of ground or opal glass-
I require for my purpose an incandescent lamp in which the carbon consists either
of a single straight filament, or, if the filament is bent, its two sides should be
parallel and as close together as possible; the object in each case being to obtain a
long, narrow and straight line as the source of light-The bulb in which such
filament is enclosed should itself have by preference a form more or less cylindrical
as compared with the more or less. globular forms at present in use- -With such a
lamp I combine a lamp glass which slides over the lamp, and has either convex ribs
or concave grooves on one or both sides of the glass (but not convex on one side and
concave on the other) such grooves or ribs running parallel to the long and narrow
filament It, is clear that the action of the lamp glass will be to spread out the
-narrow intense-line-of-light-into-a-sheet-of light which-is-less-intense-and-therefore
. less trying to the eye, but in which the total amount of light will be about the
same.
Supposing the lamp glass to be cylindrical and to have a diameter of from two to
three inches (the filament occupying the position of the axis of the cylinder) then
the best effect will be produced when the ribs or grooves have a curvature due to a
radius not exceeding one tenth of an inch-I prefer the shape of the glass to be
cylindrical, but it may consist of a number of flat sides-In all cases I combine the
long and narrow wick or filament with ribs or grooves on the lamp glass running
parallel with it.
I will now proceed to describe my invention with reference to the accompanying
Drawing.
!
Figures 1, 2 and 3 represent filaments suitable for my purpose, and figures 4
and 5 are such filaments placed in suitable bulbs-Figure 6 is the lamp glass to be
supported concentrically around the bulb, having ribs running longitudinally and
parallel with the filament-These ribs are shown in section in figure 7 and should
have a curvature due to a radius not greater than inch-Figure 8 is a section of
a glass having grooves instead of ribs, but with a similar curvature.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
Not the form of incandescent lamp above described, or the form of the glass,
either or each, by itself; but what I claim is the combination of the two for the
purpose and in the manner above described.