AN IMPROVED, ILLUMINATING ROOF AND ROOF PAVEMENT,
Year: 1867

page_text: LETTERS PATENT to Benjamin Franklin Stevens, of No. 17, Henrietta
Street, Covent Garden, in the County of Middlesex, Gentleman, for the
Invention of "AN IMPROVED, ILLUMINATING ROOF AND ROOF PAVEMENT, "__
A communication from abroad by Thaddeus Hyatt, of Atchison, Kansas,
in the United States of America.
Sealed the 3rd March 1868, and dated the 7th September 1867.
PROVISIONAL SPECIFICATION left by the said Benjamin Franklin Stevens
at the Office of the Commissioners of Patents, with his Petition, on the
7th September 1867.
I, BENJAMIN FRANKLIN STEVENS, of No. 17, Henrietta Street, Covent
Garden, in the County of Middlesex, Gentleman, do hereby declare the nature
of the said Invention for "AN IMPROVED ILLUMINATING ROOF AND ROOF PAVE-
MENT," a communication to me from abroad by Thaddeus Hyatt, of Atchison,
Kansas, in the United States of America, to be as follows:-
This Invention has reference,―
1st. To the construction of illuminating roofs.
2nd. To the mode of uniting such roofs to the side walk or footway; and,
3rd. To the mode of utilising the light obtained through such roof paveinent
for the illumination of the basement room, or other locality situate below the
level of the pavement.
In carrying out this Invention I employ chiefly glass and iron, so distributed
as to equalise the strength of the roof and its illuminating properties. The
[Price 8d.

page_text: openings, which should by preference be small enough to prevent burglary,
may be in the form of an iron grating, the openings or spaces in which are
filled in with thick glass, and when used as a footway or portion of the foot-
way I unite it to the general solid or framework by means of a double cemented
joint in which the horizontal portion is filled with putty or its equivalent,
and the vertical portion with a fusible cement composed of nearly equal pro-
portions of sulphur and coal tar. This union of the illuminating roof to the
framing is also effected by the aid of bolting in combination with the double
cemented joint; I also use illuminating tiles which serve as the covering to
the iron framing; they may be cast long and narrow so as to be as thin as
possible in order to better spread the light. In order to utilise the light
passing through the illuminating roof pavement for illuminating the basement
of a building, I make the vault under the footway with a flat roof as thin as
practicable, so that the light as it falls into it may spread rapidly, and so that
rays of light at a very low angle may enter. This vault is also made with an
open side corresponding to an open side in the basement, so that the two may
form one chamber, that portion which is under the pavement forming an
illuminating chamber which reflects its light into the basement; I also arrange
that portion of the footway which I form into an illuminating roof so as to be
placed next to the building, where it forms an area platform or may be com-
bined with illuminating "sills," "risers," or "treads."
In setting the glasses in the tiles I employ two methods, viz., one wherein
the glasses are belted each with a band of lead; the other where they are
bedded on putty, and the vertical seam round the glass in its seat in the iron
is filled with the fusible cement before mentioned.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Benjamin Franklin Stevens in the Great Seal Patent Office
on the 7th March 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BENJAMIN
FRANKLIN STEVENS, of No. 17, Henrietta Street, Covent Garden, in the
County of Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of September, in the year of our Lord
One thousand eight hundred and sixty-seven, inthe thirty-firstyear of Herreign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Benjamin Franklin Stevens, Her special license that I, the said Benjamin

page_text: Franklin Stevens, my executors, administrators, and assigns, or such others asI,
the said Benjamin Franklin Stevens, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britainand
Ireland, the Channel Islands, and Isle of Man, an Invention for " AN IMPROVED
ILLUMINATING ROOF AND ROOF PAVEMENT," a communication from abroad by
Thaddeus Hyatt, of Atchison, Kansas, in the United States of America, upon
the condition (amongst others) that I, the said Benjamin Franklin Stevens,
my executors or administrators, by an instrumentin writing under my hand and
seal,should particularly describe andascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent..
NOW KNOW YE, that I, the said Benjamin Franklin Stevens, do hereby
declare the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say:-
The said Invention has reference to the construction of illuminating roofs,
to the mode of uniting such roofs with the side walk or footway, and to the
mode of utilising the light obtained through such roof pavement for the
illumination of the basement room or other locality situate below the level of
the pavement.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose shall
refer to the several Figures on the annexed Sheet of Drawings, the same
letters of reference indicating corresponding parts in all the Figures.
Figure 1 of the Drawings represents a plan of an area or platform light
intended to be employed in connection with the "sills" and "risers" to form
the illuminating portion of a roof side walk; Figure 2 is a longitudinal section
of the same taken along the line 1, 2; and Figure 3 is an end view; these
Figures represent the manner of uniting several illuminating gratings into
one by means of a frame of cast iron. Figure 4 is a section of a portion of
the frame (full size) showing the grating k, k, on a bed of putty g, g, the
upper portion of the joint being filled with a fusible cement f, f, composed of
coal tar and sulphur. C, C, is the frame, and D, D, are cross bars which
divide the space into sections corresponding in size to the gratings. d, d, is
the rebate or seat in which the grating is held on its putty bed; and to which

page_text: it is bolted. e, e, are lugs to receive the bolts h, h. i, i, represents the putty
bed on which the glasses I rest in their seats. ), j, is the fusible cement
around their sides. In Figure 1 only one of the spaces is shown with a
grating, and the glasses in this are represented as being diamond shaped, but
generally they are circular or hexagonal. Figure 3 at F shews a rising lip
(seen more perfectly in the enlarged view at Figure 5), to which lip the
riser R is bolted as a support or beam. The manner of connecting the
platform, the riser, and the sill is also clearly shewn in Figure 5. Figure 6 is
a sectional elevation showing the stone side walk H, and the room or vault
space I' beneath. The illuminating platform is represented at C; B is the
basement inside the building, and K. the principal story or ground floor.
The red lines are destined to shew the manner in which light enters the
basement. L, represents the illuminating sills; R, the risers; G is the nosing
on the front edge of the platform and sill. Figure 7 is a front view of
Figure 6 shewing the risers R as they appear in line across the front of the
building, also the line of the flooring of the principal story or ground floor,
and the pitch of the street, shewn by the line 1, 2. Figure 8 is a plan shewing
the side walk, both dead work and light work.
One of the main objects of this Invention is the enlargement of a building
plot by incorporating with it a portion of the street through the agency of an
improved illuminating roof pavement, in which I employ an improved method
of constructing and combining iron gratings set with glass and in the manner
of combining the glasses with the iron grating. By organizing the materials
of the side walk into a roof, and connecting this with the main building as an
organic portion of its construction, all necessity for closing the front of the
basement story is avoided for the side walk in its roof capacity is an effectual
protection against the weather.
One of the improvements therefore consists in extending the basement
under the street by means of a three-walled apartment, whose roof is the
side walk and whose boundary on its open side is the open basement. In
constructing buildings on this plan the street space is included in the excava-
tion, and the foundation is laid so as to inclose the whole. The side walls of
the apartment under the street are extensions virtually of the side walls of the
main building, on these the side walk mainly rests. The side walk is designed
to serve the double purpose of roof and "trottoir," the upper surface forming
the actual side walk or "trottoir" of the street, whilst the lower or under
surface forms the actual ceiling to the apartment below; this roof side walk
is divided into two parts, one of which is dead work and the other translucent.
Upon the side walls of the extension I lay an iron girder M, Figure 6, which

page_text: has a single or double flange at the bottom; this girder is placed parallel with
the face of the main building and at such distance from it as to give the
required space for light. On the other side of the girder I make the dead
work. The Drawings shew this work as made by four stone slabs, but iron
beams and plates may be substituted. When I use iron beams and brick
arches I prepare the bricks with asphalte by dipping the dry bricks on one
edge into hot asphalte, and then lay them in cement in the usual way, but so
placing each brick as to present the asphalte face uppermost; the arches are
then in good condition to receive a coating of asphalte over the whole which
will render them water-tight. Upon the surface of the asphalte while hot I
lay iron gratings which are bolted to the iron beams and level off the asphalte.
flush with the face of the gratings; this makes a water-tight and durable side
walk with a good foot hold.
The translucent parts consists of illuminating sills, risers, and platform, the
last has a nosing G upon its front edge which overlaps the edge of the street
girder M on which it rests, and a rise F on the opposite side where it is bolted
to the illuminating risers, as shewn in Figures 3 and 6. The risers R are
also bolted to the sills L, these both are also bolted to the pillars on which
they rest by which they act as ties to the pillars. All the exposed joints are
made water-tight by the double cement. The translucent portion of the roof
side walk becomes thus a portion of the main construction. As to the size of
the openings in the gratings and the kind of glass, small openings and small
glasses are best. In a foot pavement one inch and a half diameter is large
enough, and for roofs three inches; larger openings and glasses are dis-
advantageous. The glasses are set in the double cemented joint and are bedded
in putty, and the vertical seam is filled with a fusible cement of coal tar and
sulphur. The gratings are combined by means of bolting or rivetting in con-
junction with double cement packing, and the improvements in the gratings
consist in making illuminating sills, risers, and platforms to form illuminating
stoops, and illuminating risers and treads in forming illuminating steps.**
With reference to illuminating roofs constructed of glass and iron as
commonly made I may remark that the "framing" is wholly in the iron and
the filling in is wholly in the glass; the result of this is that such roofs are
not fire-proof, the general surface being glass; they are also weak and fragile;
moreover, when made in an arch or in the dome form it is necessary to bend
the glass which adds to the cost.
;
The improvement in roofs constructed of iron and glass consists in making
the general surface of iron instead of glass, the strength of the structure is
thus put into the iron entirely, and this also makes it fire-proof; I accomplish

page_text: this end by using the illuminating gratings or tiles as a filling in to the iron
"framing." In this way I am able to make dome roofs and arched roofs without
any change either in the glasses or in setting them, the dome and the arch
being wholly in the form of the iron made by casting or forming the gratings
upon suitable curves. I also make these gratings out of sheet metal by
striking up the seats for the glasses.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that what I consider to be novel and
original and therefore claim as the Invention secured to me by the herein-
before in part recited Letters Patent is,-
First. The general construction, arrangement, and mode of applying
illuminating roofs and roof pavements, substantially as and for the purpose
herein-before described and illustrated by the Drawings.
Second. The application and use to and in the setting of glasses in metal
frames, and in the setting of one metal frame or holder within another of
double cemented joints, as herein-before described and illustrated by the
Drawings annexed.
Third. The combining of a series of illuminating gratings or tiles com-
posed of glass and metal with iron frames, girders, and beams disposed over
an apartment formed underneath the side walk, so as to constitute an
illuminating roof side walk, the whole being united to the building in such a
manner as practically to extend the basement under the street; also the com-
bination of such illuminating gratings or tiles and iron frames, girders, and
beams for the forming of roofs for ordinary apartments or chambers,
substantially as herein-before described and illustrated by the Drawings
annexed.
Fourth. The peculiar mode of combining glass and iron so as to form
illuminating sills, risers, and steps, as herein-before described and illustrated
by the Drawings annexed.
In witness whereof I, the said Benjamin Franklin Stevens, have to this
my Specification set my hand and seal, the Sixth day of March, One
thousand eight hundred and sixty-eight.
B. F. STEVENS. (L.S.)