IMPROVEMENTS IN APPARATUS FOR DIFFUSING LIGHT
Year: 1881

page_text: LETTERS PATENT to Jasper Wetter, of New Wandsworth, Surrey, for an
Invention of " IMPROVEMENTS IN APPARATUS FOR DIFFUSING LIGHT."
A communication from abroad by William Wheeler, of the State of
Massachusetts, United States of America.
PROVISIONAL SPECIFICATION left by the said Jasper Wetter at the Office
of the Commissioners of Patents on the 5th September 1881.
JASPER WETTER, of New Wandsworth, Surrey. "IMPROVEMENTS IN APPARATUS
FOR DIFFUSING LIGHT." A communication from abroad by William Wheeler, of
the State of Massachusetts, United States of America.
This Invention relates to a system of lighting, and to a special apparatus whereby
any desired amount of the light producing energy employed is converted into light
vibrations at a central or single place, from which the light generated is transmitted
and distributed to and dispersed at any number of places which it is desired to
illuminate by optical conduction, division, and dispersion of light.
The Invention consists, first, in a prolate ellipsoidal reflector or holophote, whose
reflecting surface is approximately such as would be generated by the revolution
about its major axis of that part of an elliptic curve included between the lutus
rectum and the minor axis, the light source being placed in a focus of the reflector.
Near the opposite focus is a concave lens mounted in an adjustable sleeve con-
nected with the wide end of the reflector by a number of arms. Between the
light source and the minor axis is a convex lens of such a diameter as to intercept
all rays sent by the light source to the wide end (minor axis) of the reflector, and
to refract them towards the secondary focus, said convex lens being secured to
arms attached to an adjustable ring which surrounds the wide end of the reflector.
The smaller opening or end of the reflector (which does not extend beyond its
focus) is covered by a hemispherical cap hinged to the reflector and reflecting on
its hollow inner surface the rays that fall near the end of the major axis. Between
the minor axis and the concave lens three parallel glass discs are mounted so as to
intercept the rays, said discs leaving between themselves two flat spaces, one of
which contains an athermanous liquid and the other a fluorescent liquid.

page_text: Also in a light transmitting tube consisting of a tube of glass, a metallic
reflecting coating encompassing its outer surface, and a circumscribing coating of
asphalt or varnish, and an additional metallic coating surrounding the asphalt or
varnish coating.
Also in the combination with a light transmitting tube of a series of curved
light reflecting branches arranged with such light transmitting tube so as to
divide and conduct the pencil of light passing from it and conduct it off in separate
beams or to dispersers.
The object of the reflecting surface in the light transmitting tube is to provide
against the non-parallelism of the rays which are sent into transmitting tubes by
lenses or mirrors, and to render imperfectly straight or bent tubes applicable for
the transmission of light.
The Invention relates also to the peculiar arrangement of lenses or mirrors for
diverting or dividing pencils of light. These lenses may be fixed or adjustable,
and single or arranged in echelon, the latter for transmitting pencils of large
volume. For diverting a pencil of light at a right angle, the lenses are inserted
through an aperture in the sides of the elbow of a pipe and secured by a press block
and set screw. Adjustable lenses are preferably used in three-way or four way-
couplings. The lense or set of lenses is mounted in a tubular lining inside a
branch pipe, which lining can be moved across the mouth of the main pipe so as
to deflect the whole or any desired portion of the light in the required direction.
The lens or set of lenses is inserted into the tubular lining through a lateral
opening and secured by a press block and one or more set screws. Where the
direction of the main beam remains unchanged while branches are deflected right
and left, the set of lenses as well as the tubular lining has a central opening for
giving passage to the main beam. For dispersing and distributing the light into
the spaces to be illuminated, the beam of light is made to fall upon or into a
dispenser secured to the mouth of the branch pipe. Said dispenser may be
spherical and made of polished metal or of hollow glass silvered on the inside, of
white chalk or lime, or similar substance, to give a diffused reflection, or of solid
glass to dispense the light by refraction. For brilliant prismatic effects a poly-
liedron of cut glass may be used. The form of the dispenser may be varied also
according to the manner and direction in which it is desired to distribute the
dispersed light. The dispenser may be of conical or wedge shaped tube of glass
attached with the open end to the mouth of the light transmitting tube, and closed
-at-the-other-end.-The-inner-surface_of_the_tube is ground or corrugated.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Jaspor Wetter in the Great Seal Patent Office on the 3rd March
1882.
JASPER WETTER, of New Wandsworth, Surrey. "IMPROVEMENTS IN APPARATUS
FOR DIFFUSING LIGHT." A communication from abroad by William Wheeler, of
the State of Massachusetts, United States of America.
This Invention relates to a system of lighting, and to a special apparatus whereby
any desired amount of the light producing energy employed is converted into light
vibrations at a central or single place from which the light generated is transmitted
and distributed to and dispersed at any number of places which it is desired to
illuminate by optical conduction, division, and dispersion of light.
This system is adapted to any source of light, but wherever any special
modification of parts are required or affected by the form or kind of light source,
they are adapted in this Invention to the use of the electric arc, and hence to that
source these Specifications may be understood especially to refer.
It is well understood that electric light may be produced through the use of
dynamo-electric machines cheaper than light from gas or any known method by
combustion. This requires however that the light be produced in voltaic arcs of
great power and intensity, for if more than one arc is maintained with the same
current of electricity, the light generated becomes rapidly less, and therefore dearer
as the number of arcs of light is increased. It is in the nature of the electric
current therefore that for the economical generation of light it should be used in
great intensity in one point instead of small intensity in many points.
(The law may be approximately stated thus:-The heating effect of the electro-
current is proportional to the square of the amount of current multiplied by the
resistance, while the lighting effect bears to the heating effect much the same
relation as the heating effect does to the amount of current. Hence the light varies
by some function greatly exceeding the square of the amount of the current, times
the resistance).
P
Hence with a given amount of current it is evident that its economical division
for lighting is very limited, and that improvements must be sought by utilizing
an arc in which the highest possible temperature is produced within the most
limited space practicable.
On the other hand, perfection in artificial lighting, optically considered, consists.
of light of low intensity radiating from many points in all directions, so that there
is an inter-crossing of rays producing a mean amount of light everywhere, and
projecting no abrupt or striking contrasts of light and shadow. Such distribution
approaches inost nearly to the indirect radiation of sun light from the atmosphere
when the direct rays are partially intercepted and dispersed by a summer cloud,
and also requires the least amount of light to produce an equal degree of
illumination. It has been proved that for lighting large open areas, as in public
squares and streets, by increasing the number of lights five times but half as much
light was required in the aggregate to produce an equally perfect and satisfactory
illumination.
The same consideration holds whether the electric current be employed to
produce the voltaic arc or to cause incandescence of carbon platinum or other
refractory solids, although the voltaic arc is far more economical as a producer of
light than any devices for incandescence.
Owing to the dazzling brilliancy of the electric arc at short distances, and the
cost of the appliances and their maintenance, the incandescent system is better

page_text: adapted for house lighting by direct radiation, while the voltaic arc can compete
with gas light only when it is required to light large spaces without partitions or
sub-divisions of the space illuminated.
Now it is the object of this Invention to obviate these objections to any of the
aforesaid systems of electric lighting, and to provide apparatus whereby is secured
that degree of economy attending the generation of light in voltaic arcs of great
power and intensity, and the greater optical perfection of artificial lighting due to
the radiation of light of low intensity from many different points, together with
other important advantages to be specified hereinafter.
The division of the direct light from an artificial source into two or more beams
or pencils by means of lenses, prisms, and other reflectors, by which said beams are
transmitted through enclosed passages and clear space to dispersing reflectors or
refractors, so as to produce two or more secondary lights from one luminary or
source for lighting purposes has been in practical use heretofore, and has been
claimed also under a United States' Patent.
In all cases of this kind heretofore known, however, only such rays of light as
are parallel, or very nearly so, can be utilized for producing a distant secondary
light. The non-parallel rays pass out of the limits of the pencil of useful rays and
are either absorbed by the opaque non reflecting surface which enclose the beam
when it is transmitted through an enclosed passage, or is lost in space when
projected through clear space toward the dispersing object. But it is impossible to
derive a beam of parallel or even mostly parallel rays of light from an artificial
source, such as a flame, an electric arc, or an incandescent or a fluorescent
substance. Such sources have a certain extent of surface, from every point of
which light radiates outward and in every direction, so that any point near it
receives rays converging from every point of the said surface exposed toward. it.
Hence the total angular variation from parallelism of reflected or refracted rays
emanating from such a source is at least equal to the parallax of the point of
incidence at which reflection or refraction first occurs measured from said source of
light. From this it is evident that a very large proportion of the whole light.thus
treated by methods heretofore used or proposed is lost when it is attempted to
transmit the pencils or beams through tubes or passages whose lengths are great as
compared with their respective diameters.
Furthermore, the parallel rays are more or less intercepted by unavoidable
deviations and irregularities in the alignment of said tubes or passages, and
-displaced-or-deflected-out-of-parallelism with the axis of such tubes and passages
by imperfections in the adjustment of lenses, prisms, reflectors, &c.
Now it is further, therefore, one of the chief objects of this Invention to
obviate all these objections to other methods and systems for the optical
division, transmission, and dispersion of light for lighting purposes, and further to
derive and utilize a desirable advantage from the non-parallelism of rays
aforesaid.
Referring to the Drawings,
Figures 1 and 2 comprise a general isometric view of this Invention, Figure 1
representing the halophotal and condensing apparatus, and Figure 2 the conducting,
distributing, and dispersing or radiating apparatus.
Figures 3, 4, 5, and 6 represent in detail the holophotal apparatus, Figure
showing a critical longitudinal section, Figure 4 a plan view as seen from above,
Figure 5 a rear elevation, and Figure 6 a modified combination for the projection
of two primary beams in opposite directions.
Figures 7 and 8 represent longitudinal sections of the pipes or tubes used for the
transmission and distribution of the light.
Figures 9 to 34 inclusive represent in detail the various parts in some of
their combinations used for the subdivision, deflection, and dispersion or radiation
of beams of light. Of these Figures, 9, 10, and 11 represent a right angled
coupling, in which is mounted a series of right angled total reflection prisms
set in echelon, by which a beam of light is deflected at right angles, Figure 9

page_text: showing a longitudinal section, Figure 10 a side elevation, and Figure 11 a
transverse section by a plane bisecting the internal angle of the coupling.
Figure 12 represents a vertical longitudinal section of an adjustable four way
branch with two series of total reflection prisms set in echelon, by which a single
beam, pencil, or tube of light may be divided into three lesser ones. Two of these
secondary beams are deflected at right angles to and in opposite directions from
the primary pencil or beam of light, and may be varied in the ratio of their
intensity to each other, while the third beam is in direct continuation of the
primary one and is invariable in its amount or intensity, except by means
hereafter to be shewn. A condenser is shown attached to the right hand end, by
which the lateral dimensions of the transmitted beam are reduced.
Figure 13 is a vertical transverse sectional view of the foregoing.
Figure 14 represents a vertical longitudinal section of an adjustable three way
branch with two series of prisms set in echelon, by which a single beam of light
may be divided into two secondary beams or pencils deflected at right angles to
and opposite in directions from the entering beam, and having any desired ratio
of intensity or amount of light to each other. A condenser is shewn attached to
one end.
Figure 15 represents a vertical transverse section of the same.
Figure 16 represents a longitudinal section of an adjustable three way branch
with two single prisms, by which a single beam of light may be deflected, as
in the last preceding instance, without subsequent condensation. A reducer is shewn
attached.
Figure 17 shows a transverse section of same.
Figure 18 represents a longitudinal section of an adjustable three way branch,
with a single prism, by means of which the whole or any part of entering pencil or
tube of light may be deflected at right angles to the entering beam, and the
remainder allowed to pass on in continuation.
Figure 19 is a transverse sectional view of the same.
Figure 20 is a longitudinal sectional view of a four way adjustable branch,
with two single prisms set in separate mountings, by means of which the
whole light received may be deflected to the right hand or to the left, or allowed
to pass between them in continuation and unaffected, or divided between the
three outlets in any desired proportion. This is a double form of that shown in
Figure 18.
Figures 21 and 22 represent a right angled coupling in which is mounted or
set a single total reflection prism, by which the entering light is deflected at right
angles.
Figure 23 is a vertical sectional view of a five way non-adjustable branch, with
four wedge shaped total reflection prisins, by which the light received is deflected
equally in four different directions. It is here represented in combination with
reflecting despensers mounted in the paths of the pencils of light, the whole
constituting a four light chandelier.
Figure 24 represents a horizontal section of the same as viewed from beneath
the chandelier.
Figure 25 shows a vertical sectional view of a five way non-adjustable branch,
by means of which the beam of light received is divided and transmitted in any
desired directions without the use of prisms or special reflectors. The branch is
shown in combination with the reflecting dispensers, the whole representing a four
light chandelier.
Figure 26 is a plan view of the same as viewed from above.
Figures 27 and 28 represent a section and an elevation respectively of a
reflecting dispenser.
Figures 29 and 30 are views of modified forms of reflecting dispensers.
Figures 31 to 34 inclusive represent various forms of what I terin tapering
dispensers, operating in a manner hereinafter described.
In further explanation of the construction and operation of the apparatus,

page_text: Figures 1 and 2 may be supposed to represent part of a system adapted for and
placed in a dwelling house of two stories."
The electric light A is maintained in the principal focus of the holophote or
reflector B, which is supposed to be placed in the basement. It may be in any
convenient place in or out of the house.
Said holophate consists of the following parts, namely:-
B is a prolate ellipsoidal reflector, whose reflecting surface is such as would be
generated by the revolution, about its major axis, of that part of an elliptic curve
included between the latus rectum and' the minor axis. These limits of the curve
may however vary at either end and in either direction C is the position of the
other focus of the ellipse, which I shall designate the secondary focus; D is an
adjustable ring, collar, or sleeve fitting over and around the front or aperture (end)
of B, and is held by the binding screws a, a, a, which pass through the oblique or
screw adjusting slots b, b, b, in said sleeve, and screw into the part B. This
construction may be varied by causing the sleeve D to fit inside an enlargement at,
and of the aperture of B, in which enlarged portion oblique adjusting slots are cut.
The screws a, a, a, are then screwed into the ring D.
Secured to the ring D by screws or otherwise are the double arms E, E, E, E, anḍ
extending in both directions, as shown. At their inner ends held in notches cut
in said arms or by equivalent means, the convex lens F is supported vertically
with its centre in the major axis of the ellipse, and at their outer ends they are
connected by screws or other equivalent means to the ring or collar I, in which the
adjustable mounting J revolves, containing the concave lens G properly centred,
while between the latter and the aperture of the reflector B the ring H is fixed as
represented.
The size and position of the lens F is such that its periphery lies in the inter-
sections of straight lines drawn from the focé to the periphery of the opposite ends
of the reflecting surface of B, as represented.
Now the property of a reflector of the above construction is such that rays of
light emanating directly from the focus A and falling on B will be reflected
exactly toward the other focus C. All focal rays radiating toward the open
aperture of the reflector are intercepted by the lens F, by which they are refracted
and thereby made also to converge toward the secondary focus C.
The diameter therefore of the lens G is made somewhat greater than that of the
primary beam or pencil of light to be transmitted through it; is position is such
-as-so-intercept the pencil of rays converging toward C at a point where its
diameter is less than that of the lens G, and the curvature-of-the-said-lens_is_
such that rays from the exact focus at A are made parallel in their passage through
it.
The focal adjustment of F is effected by turning the ring D about the major
axis through the action of the screws a, a, a, in the slots b, b, b. The position
of G is then corrected and adjusted by screwing its mounting J further into or out
of the ring or collar I as may be necessary.
The lateral movement allowed by the screw threads on J is about double that
by the slots b, b, b, for the reason that the former must be moved both to the
extent required for the adjustment of G, and also to counteract the movement to
which it is subject in the preceding adjustment of F.
The ring H is provided with three shoulders turned upon its interior surface, as
shown. Against these are hermetically fitted three parallel discs of glass c, c, c.
Two thin discs of space are thereby enclosed. They may be filled through cocks
set in the side of the ring or otherwise.
In one of them is an athermanous liquid or solution interposed in the pencil of
light for the purpose of obstructing heat rays. In the other a fluorescent liquid
or solution is combined, whereby obscure violet or other non-luminous rays than
heat rays are converted into luminous rays. The refractive effect of these discs of
glass and liquid changes slightly the focus of the converging pencil, which may be
counteracted and corrected at 1, as above specified.

page_text: At the back of the holophote, when only one beam of direct light or one primary
pencil is required, a hemispherical reflector K is fixed by means of the pivot hinge d
and the separable hinge e, the centre of K coinciding with the prime focus A. The
object of the reflector K is twofold; first, to reflect as much as may be of the
direct light which it receives back again through or by the field of the arc to form
a part of the pencil of useful rays; and, second, to reflect back again into the field
of the arc the heat received, so as to maintain a higher temperature in said arc,
and thereby increase its light power. The reflector K may be swung open on the
hinge d (for the removal of carbons in the attached regulator, or for other
purposes) after withdrawing the eye pin f and separating the hinge 6. At g is
shown a small orifice in the exact center of the hemispherical reflector K used to
aid in adjusting the line of collimation of the several parts, and to keep the electric
arc accurately focussed.
When two primary beams or pencils are required, the reflector K is to be
entirely removed after removing the pins of both hinges; and to the remaining
portion of the holophote, a second or duplicate holophote, precisely like the first, is
to be connected and joined thereto in the place of the removed reflector K, all
being as shown in part in Figure 6, the hinge sections being so alternated on the
opposite sides as to fully admit of such an interchange of parts.
I have already described the course followed in the holophote by rays
radiating from the exact focus of the electric arc A, which is also shown in the
Drawings, Figure 3, by dotted lines.
At the incident points h and i rays of light radiating from the outer limits
laterally and from opposite sides of the voltaic art are represented as falling. It
will be observed and understood that such rays will not and cannot be reflected
toward the same point as focal rays falling upon the same points and i. Hence
such rays will not and cannot be refracted by the lens G so as to become parallel
with each other or with the axis of the holophote. On the contrary, such rays
meet the surface of the lens G at such points and at such angles of incidence that
the error of their direction will be increased by either too great or too little
refraction, as is shown in the Drawings. The same is true of such rays first
incident upon the lens F and then refracted toward G.
Now it is clear that for every ray of light which radiates toward any point of
the reflector B or lens F in an exact line with the prime focus at A, there must
be an infinite number of rays which radiate to the same point from the rest of the
arc, and therefore which are not in line with said focus. None of these will be
made parallel with the axis of the holophote on leaving the lens G. It is to be
understood that the term rays as here applied to the emanations of light is not used
in a technical but popular sense, in order to give a more concrete form of
expression to and a clearer comprehension of my meaning without violating
practical truth and accuracy.
Hence, it appears that there is projecting from the holophote at G a condensed
beam or pencil of light, consisting of, necessarily, an infinity of parallel rays, together
with an infinitely greater number of rays not parallel to those or to each other.
It is therefore evident that an efficient system, or method, or apparatus for
conducting light in small condensed beams, or pencils, or tubes, to any considerable
distance as compared with the diameter of said beams must provide for the
transmission and utilization of the rays that are not parallel with the axis of such
beams, pencils, or tubes of light.
Figures 7 and 8 show how this is accomplished in this system and by this
apparatus.
Figure 7 represents a longitudinal section of the right angled coupling L
carrying a series of total reflection prisms and connecting the two straight tubes M
and Al, to the latter of which curved and straight tubes are joined in succession
by the straight coupling O, O¹, etc.
The characteristic feature of the tubes, pipes, or passage ways M and M, N, etc.,
used in this Invention for the transmission, conduction, and distribution of light, is

page_text: an internal reflecting surface. The object of said reflecting surface is to avoid
loss of light by absorbtion by reflecting rays falling thereon, whether by reason
of being out of parallel with the axis of the tubes or passages, as shown at h¹ and h¹¹
and and, or because of inaccuracies or imperfections in their construction or
adjustment, or in that of other parts of the apparatus, or for the express purpose
of changing the general direction of the pencil or tube of light by the use of the
tube only, as shown at N. This last result is also secured by using straight
sections of pipes set consecutively at slight angles of deflection with each other.
Tubes or passage ways of any desired form of cross-section, made of any suitable
material, and provided with any desirable or convenient form of reflecting surface
upon the interior may be used.
This Invention especially refers to the form of tubing shown in the Drawings
and described below.
It consists of an annealed or toughened glass tube j of good quality and suitable
thickness, upon the outer surface of which is deposited a layer of metallic silver k
by any suitable silvering process, or an equivalent reflecting body. I produce
thereby an intra-cylindrical glass mirror which gives double reflection. For the
temporary protection of the layer of silver or equivalent reflecting body, a coating
of asphalt in a drying solvent is applied, or an equivalent protection. For the,
permanent covering of the tube, and to impart adequate strength to the apparatus
an electro-metallurgical deposit of copper, iron, brass, bronze, or other metal or
alloy is made upon said asphalt or other covering, or upon the metallic silver direct,
the silver being a suitable conductor of the current of electro-deposition; or the
asphalted tube may be inserted in a metal tube of suitable size, and firmly secured
therein. Ornamental finishing by electro-plating, polishing, bronzing, or by any
process in similar cases used may be performed thereon. In said metal covering
screw threads are cut at the ends of the tube sections, whereby they are connected
by couplings to each other, and to the necessary branches, condensers, reducers,
dispensers, &c.
Figure 8 shows in detail the manner in which a ray of light in the tube, not
parallel with its axis, is reflected. The ray m passing from the right toward the
left is incident upon the inner surface of the glass n. A certain part of the ray
is reflected from the first surface in m¹, the ratio of m' to the whole ray m being
dependent on the angle of incidence. The remainder of the ray is refracted through
the glass to the silver surface at n¹, where a small part of it is absorbed and the
remainder reflected back into the tube m¹ being refracted into parallelism_with_m¹
on leaving the glass. Thus by double reflection the loss of light is much less than by
single reflection, and its use admits of dividing and changing the course of beams
with the greatest facility and economy of light power. This Invention also allows
the tubes or passage ways to be of very small size and the light to be carried in
them to the greatest possible distance, and is not liable to the production of a
dangerous or disagreeable degree of heat through the absorption of any heat rays
which may be present in the beam.
The right angled coupling L, see Figure 10, I usually make with an irregular
slot or opening in each of its opposite sides, such openings being of such form and
situation as to admit into them the prisms P, P, P, the pressure or holding block Q,
and the binding screw R, in such positions that the prisms will receive the whole
of a pencil or beam of light entering at one arm, and reflect it out at right angles
through the other. The prisms P are bevelled off across the ends of their reflecting
surfaces, as shown in Figure 11. The points of the part L which enter the angular
space between the prisins are bevelled in a corresponding manner, as represented
in the said Figure 11. The ends of the compression block Q are provided with
correspondingly bevelled projection, which bearing upon and projecting over the
bevelled ends of the prisms and of the pointed parts of the part L between the
prisms, serve to hold all parts in their proper places. The bevelled projections of
the holding block Q are a little nearer together than the correspondingly bevelled
bearing surfaces of the prisms, so that the plane intermediate surface of the prisms

page_text: Ai
and block may not come into contact with each other to mar the reflecting
property of the prisms. By turning the screw R outward against the inner
cylindrical surface of the coupling L at S, the block and prisms are secured in
place, and by reversing R the block and prisms will be released to admit
of their removal from the coupling. This method of' mounting and securing
prisms is used where a considerable number are required in one series. It may
however be used in certain cases when but one prism is required. In order to
equalize the pressure upon a series of prisms, the bevelled surfaces of the
compression block Q may be covered with a layer or cushion of yielding
compressible material, such as felting, rubber, or cork.
Figures 21 and 22 represent a simple method of mounting a single prism in a
right angled coupling for ordinary purposes. Openings of the same size and
shape as the cross-section of the prisin are to be made in opposite sides of the
coupling L Into such opening the prism is snugly and securely set and fitted, as
shewn. A series of two or more prisms set in echelon may be mounted in like
manner.
Figures 12 and 13 represent a four way main branch, in which T is a cylindrical
case open at both ends and connected not only with the receiving branch O
through which the main pencil of light enters but with an outgoing branch 011
(having its axis in a straight line with that of the branch O¹), through which a
part of the main beam passes in continuation; U is an adjustable sliding tube or
cylinder holding the reflecting prisms, and which is actuated in a longitudinal
direction by a rack in it, and by a pinion V, or equivalent means. An orifice
to admit the entering beam is shown in the side of cylinder U towards the
receiving branch, such orifice being of an oblong shape with semicircular ends. When
the cylinder U is in the middle of its allotted range of movement, or as it is
represented in the Drawings, the middle point of the said orifice lies in the common
axis of the branch O' and tube M'. The length of the said orifice is equal to the
diameter of the main tube M, plus the range of motion allowed to U, and its
breadth is equal to the diameter of M¹. Hence whatever be the position of U
within the prescribed limits the whole beam of light may enter said receiving
orifice. In the opposite side of the adjustable cylinder U is shown a smaller orifice
whose center is diametrically opposite that of the receiving aperture. P¹, P¹¹, P,
and P, are the reflecting prisms, the ends of which rest and are set in openings
in opposite sides of the cylinder U between the two orifices described above, said
prisms extending across at right angles to the axis of both M and U; Q₁ is a
pressure holding block having a bevelled projection or ledge at each end, such
projection bearing upon a corresponding bevel at each end of every prism, and
also on the angular part of the cylinder U projecting between the faces of said
prisms. The block Q' is brought and held to a firm bearing by the action of
the binding screws R', R', which react against the opposing part of the cylinder U,
as shewn, all in a manner similar to that specified in the case of the coupling L.
The two lower prisms P and PI are cut away along the middle portion of
their length next the line of their adjoining edges so as to leave an opening
between them, the length of which in the direction of the length of the prism
does not exceed. the diameter of the upper branch tube M", and the breadth of
which is not greater than the difference between the diameter of M" and the
amount of the lateral movement allotted to the adjustable cylinder U. The
pressure block Q₁ is perforated by a corresponding orifice. Hence whatever
the position of U the whole of the transmitted beam may enter the tube M¹¹, that
is to say, through the above described opening or apertures between the prisms P
and P in the block Q, and through the top of the cylinder U a certain fixed
and invariable part or proportion of the main beam or pencil of light entering
at O passes unchanged directly out of the branch 0 into the tube M, whatever
be the position of the cylinder U within the prescribed range of its motion. Of
the remainder of the main beain the prisms P¹ and p₁ reflect a certain variable
portion to the left, while the prisms P¹¹ and Pull reflect the balance to the right.

page_text: The ratio of the parts reflected in such opposite directions is governed by the
adjustable cylinder U, and hence may be varied at will within certain limits by
operating the pinion V.
It is to be observed here as an important advantage covered by this Invention
owing to the large proportion of sensibly non-parallel rays in pencils of artificial
light from any source, that whatever be the form of the cross section of such pencils
on entering a tube of the character described, by the reflection of such non-parallel
rays from side to side of the tube in their course through it, and at an infinite
variety of small angles, the whole bore of said tube in a short distance becomes
filled with the rays of light making a beam or pencil of uniform intensity. To
such beams therefore I apply the term "tube of light."
Hence also a prism which has intercepted and deflected away from a tube of such
rays a part thereof only cannot prevent another prism placed at any considerable
distance further along in the course of said tube of light from intercepting a like
or due proportion of the remaining rays, even though the latter prism occupy the
same field in the cross section as does the preceding one. Whatever light may be
transmitted through the tubes will practically be uniformly distributed throughout.
their full enclosed space, the shadows projecting behind intercepting prisms and other
parts being speedily obliterated by the diffusion and reflection of the remainder of
the beam. Thus the non parallel quality of the greater part of the rays become a
positive advantage. It also renders unnecessary and inconsequential the exact
optical adjustment of the various parts of the apparatus employed.
The four way branch described above is used in cases where a part of the beam
is required to pass on to be used at some point farther along in the line of the
main pipes M and M", as in the case of a second floor of a house, the two lateral
branches supplying light for rooms on the first floor.
Figures 14 and 15 represent a three way branch, differing from the above
described, in that no apertures or orifices are provided for the passage of any part
of the beam received in continuation between the prisms, and through the pressure
block and adjustable cylinder, as shewn. Also in that the field covered by the
prisms and the range of movement allowed to the adjustable cylinder holding them
is equal to two times the diameter of the supply tube M", hence the whole of the
beam received may be directed through either arm of the branch, or may be divided
between them in any desired, proportion. This form of branch is used where it is
not desired to extend a part of the main beam in continuation, as in the case cited
above, in which this branch may be supposed to direct the whole of the light
received for lighting the second story, none being required above that floor. Either
may be used horizontally as well as vertically however,
Figures 16 and 17 represent a form of branch similar to that last described. It
is of smaller size, however, and hence but two prisms are required, one for each of
the reflected beams. These prisms are set and secured without the use of a pressure
block and binding screws. Openings of the same size and shape as the cross section'
of the two prisms p and p¹, when placed in their proper relation to each other are
provided in opposite sides of the adjustable cylinder u in which the prisms are
securely set and fitted. The part g' between the prisms can be sprung so as to
adinit the prisms, and then made to bear upon their back surface at the ends and
so hold them securely in place; the breadth of the face of each prism is equal to
the diameter of the supply tube O, and the range of motion allowed to the
adjustable cylinder u is the same, hence the whole beam of light admitted may be
deflected through either arm of the branch, or may be divided between them in any
desired proportion.
It is to be understood that whatever be the number of prisms to be mounted,
pressure blocks may be used or dispensed with as circumstances may require. In
general for large main branches where a series of prisms in echelon is used, pressure
blocks are used to secure a more equable pressure thereon, while with small sized
branches requiring a small number of prisms adequate security may be had without
such blocks.

page_text: In the carrying out of this Invention I prefer to use throughout the parts where
necessary prisms of a uniform size of cross-section, so that for the smallest size of
tubes, couplings, and branches, one prism is large enough to reflect the whole
beam; for the next size in which the diameter of the bean is twice that of the
smallest, two prisms are used to reflect the whole beam; for the third size, in
which the beam is three times as wide, three prisms are used, and so on.
Thus
greater economy is secured in making and fitting the prisms and other parts.
Figures 18 and 19 represent a form of three way branch, by which the whole.
or any desired part of the entering beam may be taken off through the single arm
of the branch, leaving the remainder to pass on unchanged in continuation. The
prism is mounted as in the last described case, while the carrying cylinder is
terminated by a plane passing through the prism.
Figure 20 represents a double modification of the branch last described, in which
I have a four way branch with two adjustable prisms supporting cylinders, by
means of which the whole or any desired part of the entering beam may be
conducted through either of the three distributing branches, and the remainder, if
any, divided in any desired proportion between the other two. It may be described
as being a modification of that shown in Figure 16, in which case we may suppose
the cylinder u to be cut by a plane passing between the two prisms, and the left
hand portion thereof provided with a rack and pinion of its own. In this double
form of branch the two adjacent ends of the adjustable cylinders are projected just
far enough to restrain the prisms from a seveře or dangerous contact or collision,
as shown in the guard projection q and q¹¹ when brought into juxtaposition with
each other.
Figures 23 and 24 represent a five way non adjustable branch, by means of
which the beam of light received is equally divided into four reflected beams. It
consists of the cylindrical bass or hub r into one end of which light is received
through the tube O¹ and opening O". Radiating laterally from said hub r are
four branch openings and connections 8, 8, 8, 8. At and below the upper line of
said branch openings the diameter of the chamber of the hub r is enlarged, forming
at the plane of the enlargement the ledge or shoulder t. In the enlarged chamber
so formed with the outer part of their receiving sides or faces resting or bearing
upward against said ledge or shoulder are the four prisms x, x, x, x.
Said prisms
have their end cut or shaped obliquely in vertical planes and in such manner that
their receiving surfaces converge to a common point in the axis of the chamber,
while the other face of each one is presented outwardly toward its proper branch
opening. The back or reflecting surface of the prisms combine to form the sides of
a regular pyramid. The lower edges of the prisms are cut off by a plane, parallel
to their receiving faces to a sufficient extent to furnish a bearing surface, against
which the binding core or spigot t¹ presses as it is screwed into the lower end of
the hub, thus holding the prisms securely in position. This form of branch may be
used in any required position for the general division and distribution of light,
may have any desired number of prisms with corresponding branch openings and
connections; said prisms may be of equal or unequal size, and fixed according to
the amount of light it is desired to deflect by each; and the central part of the
nest of prisms around the common point of their meeting in the axis of their hub
or bass may be cut away so as to allow the passage of a beam of light in
continuation.
Figures 25 and 20 represent a simple form of non adjustable tubular branch; it
consists of a number of curved tubes a¹, four in this instance, which have each a
certain part of one end straight. Said straight portion of each tube is formed so
that its cross section has the shape of the sector of a circle, the angular dimensions
of such sectors being such that when their vertices or angular edges are brought
into a common line they form together a circular cross section, as shown in
Figure 26. The tubes may be sealed together, or may be made in the form of
one equivalent piece or tube with cross partitions, as shewn at b', or may be
separate and secured only in the mounting. They are inounted in a metal

page_text: coupling, as shewn, the solid black filling representing any suitable sealing
compound. It is to be understood that these curved tubes are of the character.
herein before described, as being a part of this Invention. In this case. the glass
tubes which constitute the foundation are first jointed together, as described above,
and afterward silvered. The metal covering is then deposited by electro
deposition or otherwise forming all into one piece. This branch may be used for
the general distribution and division of light, and may have any desired number
of arms curved in any desired direction, one (or more) of which may be wholly
straight so as to conduct and transmit a part of the main beam of light in
continuation without change of direction.
.
Figures 27 and 28 represent a form of dispenser constituting a part of this
system of lighting. It consists of the spherical dispenser y held in the bottom of
the glass tube z which is mounted in the metal holder or coupling v. The
spherical dispenser y may be polished metal or of hollow glass silvered on the
inside of white chalk or lime, or similar substance to give a different reflection, or
of solid glass to dispense the light by refraction. For brilliant prismatic effects a
polly-hedron of cut glass may be used. The glass holder z may be clear, or ground;
or opaline, as may be desired. The form of the dispenser y may be varied also
according to the manner and direction in which it is desired to distribute the
dispersed light.
Figures 29, and 30 represent a method of mounting such dispensers without
the use of glass tubes for holders. Another method of mounting is shown in
Figures 23 and 24.
Figures 31 to 35 inclusive represent another variety of dispersing, consisting of
a simple piece or tube of glass tapering from the base or open end; when it is
attached to the light transmitting tube to a closed point or edge, as shown, and
ground upon the inside; or it may be simply corrugated, or both; the inner
surfaces of the tapering or converging parts of the dispenser, by virtue of such
convergence toward the center of the pencil of light received in the same, receive
the rays of such light directly upon themselves. Now if the inner surface were
smooth or polished, even though the outside were ground, most of the light would
be reflected to the end or point of the disperser, and the dispersion would be
unequal. With the construction described however the ground or corrugated inner
surface prevents largely such reflections, causing instead an immediate diffusion
_and_dispersion of the light in all directions, and thus avoiding the necessity of a
separate reflecting or dispersing body within the tube.
Figure 31 shows a simple form tapering alike on all sides to a point.
Figure 32 represents a candle shaped form of the same.
Figures 33 and 34 represent a flat or wedge-shaped form in which the light is
received on two opposite sides thereof, and radiates in two opposite directions;
Figure 33 representing a face view, and Figure 34 an end view of the same.
Figure 35 is a vertical section of the dispenser shown in Figure 31.
It is to be understood that this Invention, as described and claimed herein, plane
mirrors or reflectors may be substituted for the reflecting prisms or series of prisms
specified herein, in which case the openings in which such reflectors are set are to
conform to any other form of holophote reflectors, or other apparatus for producing
a beam of parallel or nearly parallel rays may be substituted for that herein
described, for use in combination with tubes or conduits having internal light and
heat reflecting surfaces under this Invention.
Having thus described this Invention, what I claim as new and desire to secure
by Letters Patent is,-
1. The holophote, substantially as described, consisting of the prolate ellipsoidal
reflector B, convex lens F, and concave lens G, arranged and combined essentially
in manner and to operate as set forth.
2. The combination of the hemispherical reflector K with the reflector B, and the
lenses F and G, all being arranged and to operate as set forth.
3: The combination of the ring H provided with glass discs; the spaces between

page_text: the said discs being fitted with an athermanous liquid, or the latter and a
fluorescent liquid arranged between such discs, as set forth, with the holophote,
substantially as described, consisting of the reflector B, and the lenses F and G, ali
being arranged and to operate essentially as specified.
4. The holophote B and reflector K, provided with the interchangeable connecting
hinges d, e, and pin f, substantially as described for the purpose or purposes set
forth, such admitting of the reflector being removed from the holophote in order
for the latter to be connected with another holophote, as, hereinbefore described.
5. The combination of the holophote, constructed substantially as described, with .
tubes having inner reflecting surfaces, as set forth.
6. The combination of a holophote, constructed substantially as described, with
one or more tubes having inner light reflecting surfaces, as set forth, and with one
or more reflecting prisms arranged in such tube or tubes, and to reflect light into
or through such as explained.
7. The combination of the hemispherical reflector K provided with the sight
hole g with the holophote, substantially as described, consisting of the reflector B,
and the lenses F and G, arranged as explained.
8. A light transmitting tube consisting of a tube of glass, a metallic reflecting
coating encompassing its outer surface, and a circumscribing coating of asphalt or
varnish, and an additional metallic coating surrounding the asphalt or varnish
coating, all being essentially as set forth.
9. The combination of the covered tubular, couplings L with a series of prisms
bevelled on their ends, as described, and with a compression block and binding
screw arranged with such couplings and prism, substantially as set forth.
10. The combination of a covered tube L provided with openings on its sides
with one or more reflecting prisms arranged in such openings, as set forth.
11. Two light reflecting prisms or sets of such arranged and provided with a
passage in or between them for the transmission of light, as set forth, such being
essentially as shown in Figures 12 and 13, and as herein before explained.
12. The combination of the adjustable tube U (Figure 12) provided with one or
more lateral openings, and means of adjusting it, and with one or more reflectors
or prisms, as set forth, with an encompassing tube T, and one or two lateral
passages or branch tubes (M', M") leading from such tube T, all being essentially
as shown and described.
13. The combination of a series of reflecting prisms arranged about a common axis
with a main tube having its axis in prolongation with the axis of the prisms, and
with a series of branch tubes extending from the prisms, all being substantially as
specified.
14. The combination of a light dispenser y', substantially as set forth, with a
tube z for transmitting light in a pencil or beam of rays to such dispenser, as
explained.
15. The combination with a light transmitting tube of a series of curved light
reflecting branches arranged with such light transmitting tube, so as to divide and
conduct the beam of light passing from it, and conducted off in separate beams or
to dispersers, as set forth.
16. The combination of the enclosed sliding tube U with one or more reflectors
or reflecting prisms designed to reflect variable portions of a beam of light received
at right angles to the said tube, all being substantially as set forth.
17. The combination of an adjustable tube or carrier U with one or more
reflectors or reflecting prisms designed to reflect variable portions of a beam of light
received at an angle with the said tube, and with one or more light conducting and
reflecting tubes, substantially as set forth.
18. A light transmitting and conducting tube of glass externally coated with
silver, in combination with and enclosed in a thick tubular covering or electro
deposit of metal, in which screw threads may be formed, or with which other
devices may be joined for connecting in a continuous series by suitable couplings,

page_text: two or more of the said glass conducting tubes thus separately enclosed, all being
substantially as set forth.
19. A light dispersing tube of glass of tapering form ground or corrugated on
the inside, in combination with a light transmitting tube, substantially as set
forth.
In witness whereof, I, the said Jasper Wetter, have hereunto set my hand
and seal, this Third day of March, A.D. 1882.