Improvements in or relating to Lamps for Illuminating Purposes.
Year: 1891

page_text: Date of Application, 16th Jan., 1891
Complete Specification Left, 1st Oct., 1891-Accepted, 7th Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in or relating to Lamps for Illuminating Purposes.
A communication from JEAN BAPTISTE FERDINAND FRÉDUREAU, of 18, Rue
Lafayette, Paris, in the Republic of France, Mining Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., do hereby declare the nature of this invention to be as follows:-
This invention applies equally well to all public and private plants and arrange-
ments for the supply of light and consists in the manufacture and employment of
(1). Transparent or translucid simple or multiple envelopes or casings of any
suitable shape or colour filled with coloured or colourless liquid of any description
placed around the source of light.
(2). Simple or multiple transparent or translucid envelopes or casings either
colourless or of any suitable colour of a continuously permanently tapering or
curved shape entirely closed or open at one or more parts the external or internal
surface or both being wholly or partly formed of lenses with offsets of any
convenient shape (preferably parabolic) or of prisms having plane or curved
surfaces and producing similar optical results, the main focus common to all of
these lenses or prisms coinciding as nearly as practicable with the source of light,
such lenses or prisms being obtained by grinding or moulding; or
(3). Casings or envelopes as described in paragraph 2 either entirely or partly
filled with coloured or colourless liquid of any description.
If a source of light is placed within the transparent or translucid casing filled
partly or wholly with a suitable liquid pervious to the rays of light the light
obtained will be diffused and acquire greater illuminating power while at the same
time becoming more pleasant than if it proceeded from the source of light directly.
By placing a source of light within a transparent or translucid casing the
external or internal surface or both of which assume throughout or partly the
shape of offset lenses that is to say lenses or parts of lenses the focuses of all of
which are theoretically situated in one point and in practice occupy but a very narrow
space coinciding with the source of light the rays emitted by the latter will issue
from the casing or envelope in parallel bundles or groups in a direction which may
be predetermined at will by the position of the lenses and shape of the envelope.
In some cases the lenses may be replaced by prisms with either plain or curved
faces adapted to give similar optical results.
By this means uniform light of a maximum intensity is obtained within a
predetermined zone, while it is excluded from all parts where illumination is
unnecessary.
By combining the optical effect of the said lenses or prisms with that of certain
liquids, a very intense uniform and pleasant light is obtainable.
Instead of employing single casings with either smooth or curved and offset
surfaces, the source of light may be surrounded by a number of such casings
inserted within each other one or more of which may contain a suitable liquid,
whereby a great variety of illuminous effects may be obtained.
It should be observed in conclusion that special liquids may be used whereby
the light produced will acquire certain peculiar physical or chemical properties
which may prove of great service in many cases, for instance, in the various
manipulations connected with photography.
The external surface or the internal surface or both surfaces of the envelope
may be formed with prisms or lenses.
These before mentioned inner globes, may have either plain, lenticular or

page_text: prismatic surfaces and be filled with a suitable liquid or not, as desired. If
preferred the external envelope may be plain and smooth.
It will be understood that the shape and arrangement of the lenses and prisms
are variable indefinitely, the chief condition being that their common or main focus
should coincide as far as practicable with the source of light.
Dated this 16th day of January 1891.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or relating to Lamps for Illuminating Purposes.
A communication from JEAN BAPTISTE FERDINAND FRÉDUREAU, of 18, Rue
Lafayette, Paris, in the Republic of France, Mining Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement :-
This invention applies equally well to all public and private plants and arrange-
ments for the supply of light and consists in the manufacture and employment of
(1). Simple or multiple transparent or translucid envelopes or casings either
colourless or of any suitable colour with a conical or curved surface incapable of
being straightened, entirely closed or open at one or more parts the external or
internal surface or both being wholly or partly formed of lenses with offsets of
any convenient shape (preferably parabolic) or of prisms having plane or curved
surfaces and producing similar optical results; the main focus common to all of
these lenses or prisms coinciding as nearly as practicable with the source of light;
such lenses or prisms being obtained by grinding or moulding; or
(2). Casings or envelopes as described in paragraph 2 either entirely or partly
filled with coloured or colourless liquid of any description.
If a source of light placed within the transparent or translucid casing filled
partly or wholly with a suitable liquid pervious to the rays of light, the light
obtained will be diffused and acquire greater illuminating power while at the same
time becoming more pleasant than if it proceeded from the source of light
directly.
By placing a source of light within a transparent or translucid casing the
external or internal surface, or both, of which assume throughout or partly the
shape of offset lenses, that is to say, lenses or parts of lenses the focuses of all of
which are theoretically situated in one point, and in practice occupy but a very
narrow space coinciding with the source of light, the rays emitted by the latter
will issue from the casing or envelope in bundles or groups parallel in a direction
which may be predetermined at will by the position of the lenses and shape of the
envelope. In some cases the lenses may be replaced by prisms with either plane
or curved faces adapted to give similar optical results.
By this means uniform light of a maximum intensity is obtained within a
predetermined zone while it is excluded from all parts where illumination is
unnecessary.
By combining the optical effect of the said lenses or prisms with that of certain
liquids a very intense uniform and pleasant light is obtainable.
Instead of employing single casings the source of light may be surrounded by a
number of such casings inserted within each other one or more of which may
contain a suitable liquid, whereby a great variety of illuminous effects may be
obtained.
It should be observed in conclusion that special liquids may be used whereby
the light produced will acquire certain peculiar physical or chemical properties

page_text: which may prove of great service in many cases, for instance in the various
manipulations connected with photography.
In the accompanying drawings F indicates the source of light in all figures.
Figs. 1 to 7 show specimens of the chief forms of casings, envelopes or globes.
In order to illustrate the invention more clearly I have taken one of these forms,
viz. that shown in Fig. 1 to show the various shapes which the surfaces of such
casings may assume. This is shown in Figs. 8 to 13.
The external surface in Fig. 8 and the internal surface in Fig. 9 and both
surfaces in Fig. 10 are formed with prisms or lenses.
Figs. 11, 12 and 13 are similar views to Figs. 8, 9 and 10 with the addition of
one or more casings or globes placed within the external ones. These before
mentioned inner globes indicated in dotted lines may have either plane, lenticular
or prismatic surfaces and be filled with a suitable liquid or not as desired. If
preferred the external envelope may in the instances illustrated by Figs. 11, 12
and 13 be plane or smooth.
It will be understood that the shape and arrangement of the lenses and prisms
are variable indefinitely the chief condition being that their common or main
focus should coincide as far as practicable with the source of light and that the
surface of the casing or globe on which they are placed must be conical or curved
and incapable of being straightened.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner the
same is to be performed I declare that what I claim is :-
1. A lamp casing or envelope with a conical or curved surface incapable of
being straightened having on its inner or outer surface or both of said surfaces
parabolic or other lenses or prisms with plane or curved surfaces the main source of
light common to all of the lenses or prisms practically coinciding with the luminary
focus substantially as described and illustrated in the accompanying drawings.
2. The employment in combination with a lamp envelope casing or globe with a
conical or curved surface incapable of being straightened and having offset lenses
or prisms formed upon it of a liquid substantially as described.
3. The combination with a lamp envelope casing or globe with a conical or
curved surface incapable of being straightened and having offset lenses or prisms
formed upon
it of one or more inner casings or linings substantially as described
and illustrated in the accompanying drawings.
4. The combination with a lamp envelope casing or globe with a conical or
curved surface incapable of being straightened of one or more inner casings or
linings having offset lenses or prisms formed upon its inner or outer or both inner
and outer surfaces substantially as described.
Dated this 1st day of October 1891
W. P. THOMPSON & BOULT,
Agents for the Applicant.