IMPROVED APPLIANCES FOR DISPERSING OR DIFFUSING DAYLIGHT INTO ROOMS AND OTHER INTERNAL PARTS OF BUILDINGS."
Year: 1880

page_text: LETTERS PATENT to Robert Boughton, Architect and Surveyor, of 3, Lambeth
Hill, Queen Victoria Street, in the City of London, for an Invention of
"IMPROVED APPLIANCES FOR DISPERSING OR DIFFUSING DAYLIGHT INTO ROOMS
AND OTHER INTERNAL PARTS OF BUILDINGS."
PROVISIONAL SPECIFICATION left by the said Robert Boughton at the
Office of the Commissioners of Patents on the 13th January 1880.
ROBERT BOUGHTON, Architect and Surveyor, of 3, Lambeth Hill, Queen Victoria
Street, in the City of London. "IMPROVED APPLIANCES FOR DISPERSING OR
DIFFUSING DAYLIGHT INTO ROOMS AND OTHER INTERNAL PARTS OF BUILDINGS."
The object of my Invention is the more efficient lighting of rooms or other
internal parts of a building in a narrow street or other situation where the light is
insufficient, owing to the obliquity of the rays falling upon the windows or sky-
light. My improvement consists in the better utilization of the aforesaid oblique
rays of light, which light usually serves to illuminate only that part of the room
or other space within the building which is close to the window or skylight.
This better utilization of the aforesaid oblique rays I effect by means of an
improved form of window-glass. This consists of sheets of glass (which may be
cut into any required shapes or sizes) having formed upon them, and forming one
piece with them, certain projections or ridges, such projections or ridges being of
such a form or forms as to reflect, or refract and reflect the light falling upon them
in any required direction or directions.
The aforesaid projections may be of any form or forms which will enable internal
reflection to take place, and in section may be bounded by either straight or curved
lines, or by a combination of both; the projections on one sheet of glass are not
necessarily all of one form, but may consist of any combination of the above forms,
and may further present a wavy or zig-zag appearance in elevation for the better
diffusion of the light under special circumstances.
The action of my improved form of window glass is as follows:-
"
The light falling upon.the glass passes into it either with or without refraction,
and upon striking the internal faces of the projections is wholly and "totally
reflected; it then passes out of the glass undergoing usually a little refraction or
bending in so doing, and so passes into the room or other internal part of the

page_text: building, its final direction depending upon the inclination and forms of the
projections, which may be varied to suit varying circumstances, and where the
light is required to be thrown in any particular direction or in two or more different
directions.
In many cases I prefer placing the aforesaid glass sheets at an angle with the
front of the building, the said angle being such as will enable the glass to collect
and throw into the interior of the building the greatest possible amount of light.
This slanting position I adopt when my improved form of glass is applied to the
windows of buildings in narrow streets, alleys, courts, areas, and other positions
where they are so closely surrounded and bounded by other erections as to prevent
access of light other than that which is parallel to the face of the building, or
nearly so; in such cases, and also when the light is required to be thrown some
distance from the face of the building, the application of the glass in a vertical
position would be of little use, owing to the great obliquity and consequent great
weakness of the light falling upon it.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Boughton in the Great Seal Patent Office on the 13th July
1880.
ROBERT BOUGHTON, Architect and Surveyor, of 3, Lambeth Hill, Queen Victoria
Street, in the City of London. "IMPROVED APPLIANCES FOR DISPERSING OR
DIFFUSING DAYLIGHT INTO ROOMS AND OTHER INTERNAL PARTS OF BUILDINGS."
The object of my Invention is the more efficient lighting of rooms or other
internal parts of a building in a narrow street or other situation where the light is
insufficient owing to the obliquity of the rays falling upon the windows or skylight.
My improvement consists in the better utilization of the aforesaid oblique rays of
light, which light usually serves to illuminate only that part of the room or other
space within the building which is close to the window or skylight.
This better utilization of the aforesaid oblique rays of light I effect by means of
an improved form of glass consisting of sheets (which may be cut into any required
shapes and sizes in the manner of ordinary sheet glass) having formed upon them
by the means at present adopted for the formation of ordinary rolled glass a series
of alternate ridges and furrows, such ridges and furrows being of such forms, angles
or curves that the light falling upon the exterior or interior surfaces of the said
ridges and furrows shall by refraction or for the most part by a single reflection be
directed into any required direction or directions.
The action of my improved form of glass is as follows:-The light falling upon
the glass passes into it either with or without refraction, and upon striking the
internal face of the ridges is wholly and totally reflected; it then passes out of the
glass on the opposite surface to that on which it entered, undergoing usually a little
refraction or bending in so doing, and thence into the room or other internal part
of the building.
In other cases the rays of light are by refraction alone bent or deflected into the
direction required.
To effect this I form upon one surface of the sheet of glass a number of parallel
projecting ridges, the two sides or faces of which are, as shewn at Figure 1 of the
Drawings hereunto annexed, at different angles to the sheet of glass, one
surface being nearly at right angles to the sheet, whilst the other is inclined,
so that the ridges resemble a succession of ratchet teeth. With glass so
formed and put up in a position that light shall fall upon its plane surface in the
direction of the arrow A the light will be reflected by the narrower faces of the
projections from the opposite side of the glass in the direction shewn. If the sheet
of glass is put up in a position that light shall fall upon it in the direction of the
arrow B then the light will be reflected by the broader faces of the projections in
the direction shewn by that arrow; or if the sheet of glass be put up in position
for light to fall upon its plane surface in the direction of the arrow C then the light
will be refracted and pass from the opposite side of the glass in the direction
shewn.
In most cases I prefer that the glass should be placed in position so that the
light shall fall upon it and be reflected in the manner shewn by the arrow A.
In some cases I make the narrower faces of the ridges slightly curved, as shewn
at Figure 2.
In other cases I make the broader faces of the ridges of a curved form, as shewn
at Figure 3.
The arrows D shew the direction in which the rays of light falling upon the flat
surface of the glass would then be reflected from the opposite surface.
It is not necessary that all of the ridges or projections should be of the same depth;
they might, as shewn at Figure 4, be made deep and shallow alternately.
For some purposes I form the sheets of glass with the inclined faces of some of
the projections set in the opposite direction to the inclined faces of the other
projections, as shewn at Figure 5.

page_text: The sheets of glass are made in the ordinary manner of making rolled sheet glass.
The molten glass is poured on to a bed, the surface of which has been planed or
shaped to leave upon it a number of parallel projections to correspond with the
depressions it is required to make in the face of the sheet of glass. The glass is
poured on to the bed in front of a heavy roller, which is then caused to roll over
the bed and spread the glass uniformly over it, the surface of the roller being kept
at the required distance from the bed by strips or fillets laid upon the bed along its
sides and of a thickness equal to the thickness of the sheet of glass to be made. In
place of the projections being upon the bed plate the bed plate is sometimes smooth
and the projections are formed on the roller.
Having thus described the nature of my Invention, and the manner of performing
the same, I would have it understood that I claim,―
First. The manufacture of sheets of rolled glass with one face smooth and with a
series of parallel ridges or projections upon its other face, such ridges or projections
being formed of two surfaces which are at different angles to the smooth surface of
the glass, substantially as described.
Second. The manufacture of sheets of rolled glass with one face smooth and with
a series of parallel ridges or projections upon its other face, such ridges or pro-
jections being formed of two surfaces, one of which is curved and the other flat,
substantially as described.
Third. The inanufacture of sheets of rolled glass with one face smooth and with
ridges or projections upon its other face of the forms substantially as herein before
described and shown in the Drawing annexed.
In witness whereof, I, the said Robert Boughton, have hereunto set my hand
and seal, this Thirteenth day of July, in the year of our Lord One thousand
eight hundred and eighty.