IMPROVEMENTS IN THE ART AND MEANS OF LIGHTING CITIES BY ELECTRICITY
Year: 1880

page_text: LETTERS PATENT to Philip Middleton Justice, of 14, Southampton Buildings,
in the County of Middlesex, Patent Agent, for an Invention of "IMPROVEMENTS
IN THE ART AND MEANS OF LIGHTING CITIES BY ELECTRICITY," A com-
munication from abroad by Henry Curtis Spalding, of the City of Boston,
State of Massachusetts, United States of America.
PROVISIONAL SPECIFICATION left by the said Philip Middleton Justice at
the Office of the Commissioners of Patents on the 7th September 1880.
PHILIP MIDDLETON JUSTICE, of 14, Southampton Buildings, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN THE ART AND MEANS OF LIGHTING
CITIES BY ELECTRICITY." A communication from abroad by Henry Curtis
Spalding, of the City of Boston, State of Massachusetts, United States of America.
The object of this Invention is to light towns and cities by means of electricity
with economy, and in such manner as to cast the least possible shadows from the
buildings.
In order that a town or city may be properly lighted the atmosphere must be
flooded with a such a quantity of light irradiated in many directions as to reduce to
a minimum or practically prevent the casting of shadows. I accomplish this object
by the employment of groups of electric lights, each group consisting of a number
of lights massed together, supported at a high level, say, one hundred feet above the
houses, by means of towers of from 100 to 200 or more feet in heighth, according
to the height of the buildings, and by arranging the towers in triangular groups of
not less than three towers, whereby the rays of light cast by the electric lights of
one tower are caused to cross angularly those cast by the remaining towers; each
light tower supports a reflecting lantern containing electric lights, as hereinafter
described. The height above the streets at which these lanterns are supported
causes the light to penetrato between the buildings, and in order that such
penetration may be enhanced I prefer to arrange my light towers at the intersections
of the streets. If, say, seven light towers are combined in a triangular system,
each light tower is arranged opposite the space between the other two, so that each
three towers form a group, the members of which are at the apexes of a triangle.
By reason of this arrangement the rays of light proceeding from the lanterns of
any one of the towers are crossed by the rays proceeding from the other two of the

page_text: triangular group, and consequently the objects beneath one are lighted at different
sides, thus diminishing the shadows to the lowest practical limit. Each light
tower may be composed of four tubular sectional pillars connected by means of
horizontal braces and by diagonal screw tie rods, whose ends are passed through
cars cast upon the posts, and are drawn taut by means of nuts applied to their
screwed ends. In practice the sections of the pillars are made not less than 20 feet
in length, and their ends are formed with flanges, which are turned to fit each
other, and are connected by means of screw bolts. Each light tower supports.an
electric light lantern consisting of a gallery or floor surrounded by glass and
enclosing a group of electric lights. The lights are preferably massed in a circular
group, and this group surrounds and is external to the frame or posts of the tower,
so that these posts do not cast shadows. Each group is composed by preference of
not less than 20 electric lights of 3000 candle-power each, and the number may be
increased as found expedient. In order that the light which is radiated in an
upward direction from the electric lights may not be lost, each group of electric
lights is surmounted by a circular or conical reflector projecting beyond the groups
of lights. The reflector so arranged intercepts the rising rays of light and reflects
them angularly downward. Moreover, as each reflector is combined with a group
of lights, the rays are not only reflected downward in lines radiating centrally from
the lantern, but are radiated in directions angular to such central radial lines,
thereby reaching portions of the streets and houses which could not be reached if
the entire light of one lantern proceeded from a single central light. In order that
the lantern and reflector of each tower may be protected from the weather each
lantern is surmounted by a conical roof, whose eaves project over the rim of the
reflector and protect it as well as the lantern beneath it. Access can be had to
each lantern by means of ladders or stairs connected with the tower, and leading to
an opening in the bottom of the gallery forming the bottom of the lantern. The
electric lights may be of any improved construction, and may be supplied with
electricity from generators arranged either in buildings adjacent to the tower or
at a distance, the electricity being conducted to the lights by means of suitable
conductors.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Philip Middleton Justice in the Great Seal Patent Office on the
2nd March 1881.
PHILIP MIDDLETON JUSTICE, of 14, Southampton Buildings, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN THE ART AND MEANS OF LIGIITING
CITIES BY ELECTRICITY." A communication from abroad by Henry Curtis
Spalding, of the City of Boston, State of Massachusetts, United States of America.
The object of this Invention is to light towns and cities by means of electricity
with economy, and in such manner as to cast the least possible shadows from the
buildings. To clearly explain how these desirable results may be attained, reference
is made to accompanying Drawings, in which Fig. 1 represents a plan of a city
or town lighted upon my system; Fig. 2 represents a side view of a single light
tower; Fig. 3 represents a central vertical section of a tower lantern; Fig. 4
represents a horizontal section of a tower lantern at the line y, y, of Fig. 3; Fig. 5
represents a plan on the line x, x, of Fig. 2. In order that a town or city may be
properly lighted the atmosphere must be flooded with such a quantity of light
irradiated in many directions as to reduce to a minimum or practically prevent the
casting of shadows. I accomplish this object by the employment of groups of
electric lights (each group consisting of a number of lights massed together)
supported at a high level, say, one hundred feet above the houses, by means of
towers of from 100 to 200 or more feet in height according to the height of the
buildings, and by arranging the towers in triangular groups of not less than
three towers, whereby the rays of light cast by the electric lights of one tower
are caused to cross angularly those cast by tho remaining towers. Each light
tower supports a reflecting lantern containing electric lights, as hercinafter
described. The height above the streets at which these lanterns are supported
causes the light to penetrate between the buildings, and in order that such
penetration may be enhanced I prefer to arrange my light towers at the
intersections of the streets. This system is represented in Fig. 1, in which case
seven light towers A are combined in a triangular system. Each light tower A
is arranged opposite the space between the other two, so that each three towers
form a group, the members of which are at the apexes of a triangle indicated by
the broken lines. By reason of this arrangement the rays of light proceeding from
the lantern of any one of the towers are crossed by the rays proceeding from the
other two of the triangular group, as represented by the fine dotted lines, and
consequently the objects beneath are lighted at different sides, thus diminishing
the shadows to the lowest practical limit. Each light tower (as represented in
detail at Figs. 2, 3, 4, and 5) may be composed of four tubular sectional posts b,
connected by means of horizontal braces c, c, d, d, and by diagonal screw tie rods e,
whose ends are passed through ears f cast upon the posts, and are drawn taut by
means of nuts applied to their screwed ends. In practice the sections of the posts
are made not less than twenty feet in length, and their ends are formed with flanges,
which are turned to fit each other, and are connected by means of screw bolts.
Each light tower supports an electric light lantern G consisting of a gallery_or
floor h, surrounded by glass m, and enclosing a group of electric lights 8, 8, 8. The
lights are preferably massed in a circular group, as represented in the Drawings, and
this group surrounds and is external to the frame or posts b of the tower, so that
these posts do not cast shadows. Each group is composed by preference of not less
than 20 electric lights of 3000 candle power each, and the number may be increased
as found expedient. In order that the light which is radiated in an upward
direction from the electric lights may not be lost, each group of electric lights is
surmounted by a circular or conical reflector 9 projecting beyond the groups of

page_text: lights. The reflector so arranged intercepts the rising rays of light and reflects
them angularly downward. Moreover, as each reflector is combined with a group
of lights, the rays are not only reflected downward in lines radiating centrally from
the lantern, but are radiated in directions angular to such central radial lines,
thereby reaching portions of the streets and houses which could not be reached if
the entire light of one lantern proceeded from a single central light. In order
that the lantern and reflector of each tower may be protected from the weather,
each lantern is surmounted by a conical roof J, whose caves n project over the rim
of the reflector g, and protect it as well as the lantern beneath it. Access can be
had to each lantern by means of ladders or stairs connected with the tower and
leading to an opening in the bottom of the gallery forming the bottom of the
lantern.
The electric lights may be of any improved construction, and may be supplied
with electricity from generators arranged either in buildings adjacent to the tower
or at a distance, the electricity being conducted to the lights by means of suitable
conductors.
Having thus described the Invention as communicated to me by my foreign
correspondent, what I claim and desire to secure by Letters Patent is,-
First. The improvement in the art of lighting cities consisting in the employ-
ment of assemblages or groups of electric lights, each group consisting of a number
of lights massed together, supported in an elevated position above the roofs of
buildings, and the several groups arranged in such proximity to one another as to
light the spaces intervening between them, substantially as herein before set forth.
Second. The improvement in the art of lighting cities by electricity, substantially
as before described, by means of light towers arranged in triangular groups of three
or more, each tower supporting a lantern containing a group of electric lights.
In witness whereof, I, the said Philip Middleton Justice, have hereunto set
my hand and seal, this First day of March, in the year of our Lord 1881.
Witness,
ALLEN P. JONES,
14, Southampton Buildings,
London, W.C.
PHILIP M. JUSTICE. (S.)