IMPROVE- MENTS IN ELECTRIC LIGHTING
Year: 1881

page_text: LETTERS PATENT to Philip Middleton Justice, of 14, Southampton Buildings,
36
in the County of Middlesex, Patent Agent, for an Invention of IMPROVE-
MENTS IN ELECTRIC LIGHTING." A communication 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 6th January 1881.
PHILIP MIDDLETON JUSTICE, of 14, Southampton Buildings, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN ELECTRIC LIGHTING." A communi-
cation from abroad by Henry Curtis Spalding, of the City of Boston, State of
Massachusetts, United States of America.
In a former application (under date of 7th September 1880, and numbered 3637,)
I have described an improvement in the art of lighting towns, which consists in
the employment of groups or assemblages of electric lights, each group of a number
of lights massed together, supported in an elevated position above the roofs of
buildings, and the several groups arranged in such a proximity to one another as to
light the spaces between them.
In this system, which requires in practice the assembling in one group of quite
a large number of lights, it is neither desirable nor feasible to put all the lights in
one circuit, nor, on the other hand, is it practicable in an economical point of view
to use an independent battery or machine for each individual light. It is therefore
necessary to subdivide the group or assemblage of lights into lesser groups, each
sub group being in a circuit distinct from and independent of the others.
Under this arrangement it becomes important to prevent the fluctuations of the
lights of any one sub group from sensibly affecting the apparent amount of light
derived from the whole assemblage of massed lights. It is to this end that my
present Invention is directed, and it consists in subdividing each group or
assemblage of massed lights into lesser groups, each sub group being in an electric
circuit separate and distinct from the other, and the lights composing each sub
group being so selected as to be interspersed with and separated from one another
Drinn 21

page_text: by the lights of other subgroups. This arrangement of electric circuits may be
carried into effect in the following manner:-An assemblage of, say, thirty two
lights may be arranged in a circle, the electricity being supplied from, say, eight
batteries or machines, one to each sub group of four lights. In selecting the lights
for each sub group I take them from such points in the circle that they will be as
far as possible removed from proximity to one another.
For instance, the circuit controlled by battery A contains four lights 1, 2, 3, 4,
which are placed at four opposite points, battery B, 5, 6, 7, 8, and so on. Each
light of each sub group is thus separated from its nearest fellow. by seven other
lights of other sub groups. It is manifest that under this arrangement fluctuations
in the lights of any one sub group would exercise no sensible influence upon the
apparent amount of light derived from the whole assemblage, and that this amount
practically would remain constant; notwithstanding occasional variations in the
light of individual sub groups.
For the purpose of illustration I have mentioned four lights as being in each
circuit. It is apparent however that the number may vary. My experience on
the whole is that it is not well to have less than four lights to one machine or
battery, and on the other hand that it is not well to have less than four machines
or batteries to one group or assemblage of massed lights, but I do not wish to be
understood as restricting myself to these limits.

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
5th July 1881.
PHILIP MIDDLETON JUSTICE, of 14, Southampton Buildings, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN ELECTRIC LIGHTING." A communi-
cation from abroad by Henry Curtis Spalding, of the City of Boston, State of
Massachusetts, United States of America.
In a former application (under date of 7th September 1880, and numbered 3637),
I have described an improvement in the art of lighting towns, which consists in the
employment of groups or assemblages of electric lights, such groups 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 between them.
In this system, which requires in practice the assembling in one group of quite
a large number of lights, it is neither desirable nor feasible to put all the lights in
one circuit, nor on the other hand is is practicable in an economical point of view
to use an independent battery or machine for each individual light. It is therefore
necessary to subdivide the group or assemblage of lights into lesser groups, each
sub group being in a circuit distinct from and independent of the others.
Under this arrangement it becomes important to prevent the fluctuations of the
lights of any one sub group from sensibly affecting the apparent amount of light
derived from the whole assemblage of massed lights. It is to this end that the
present Invention is directed, and it consists in sub dividing each group or
assemblage of massed lights into lesser groups, each sub group being in an electric
circuit separate and distinct from the other, and the lights composing each sub
group being so selected as to be interspersed with and separated from one another
by the lights of other sub groups. In the accompanying Drawing is a diagram
representing the manner in which the Invention may be carried into effect. The
diagram represents an assemblage of, say, thirty two lights arranged in a circle ;
another arrangement contemplates the use of eight batteries or machines, one to
each sub group of four lights. In selecting the lights for each sub group I take
them from such points in the circle, that they will be as far as possible removed
from proximity to one another..
For instance, as indicated in the diagram, the circuit controlled by battery A
contains four lights 1, 2, 3, 4, battery B, 5, 6, 7, 8, and so on.
Each light of each sub group is thus separated from its nearest fellow by seven
other lights of other sub groups. It is manifest that under this arrangement
fluctuations in the lights of any one sub group would exercise no sensible influence
upon the apparent amount of light derived from the whole assemblage, and that
this amount practically would remain constant notwithstanding occasional varia-
tions in the light of individual sub groups. For the purpose of illustration I have
put four lights in each circuit. It is apparent however that the number may vary.
My experience on the whole is that it is not well to have less than four lights to
one machine or battery, and on the other hand that it is not well to have less than
four machines or batteries to one group or assemblage of massed lights, but I do
not wish to be understood as restricting myself to these limits. Having thus
described the nature of the Invention as communicated to me by my foreign
correspondent, what I claim and desire to secure by Letters Patent is,―
The hereindescribed improvement on the system of lighting towns by groups or
assemblages of electric lights massed together and supported in elevated positions,
which consists in sub-dividing the groups of lights into lesser groups, each sub-
group being in an electrical circuit distinct from and independent of the others,

page_text: and the lights composing each sub group being so selected as to be interspersed
with and separated from one another by the lights of other sub groups, substantially
as herein before set forth.
In witness whereof, I, the said Philip Middleton Justice, have hereunto set
my hand and seal, this Fifth day of July, in the year of our Lord 1881.
Signed and sealed in the
presence of
ALLEN PARRY JONES,
14, Southampton Buildings,
Chancery Lane,
W.C.
LIP M. JUSTICE.
(L.S.)