Edison, His Life and Inventions
by
Frank Lewis Dyer and Thomas Commerford Martin
Part 16 out of 17
many parts assembled in such contiguous proximity to each
other that an illustration from an actual machine would not
help to clearness of explanation to the general reader. Hence
a diagram showing a sectional view of a simple form of such
a camera is presented below.
In this diagram, A represents an outer light-tight box
containing a lens, C, and the other necessary mechanism
for making the photographic exposures, H<1S> and H<2S> being
cases for holding reels of film before and after exposure,
F the long, tape-like film, G a sprocket whose teeth engage
in perforations on the edges of the film, such sprocket being
adapted to be revolved with an intermittent or step-by-step
movement by hand or by motor, and B a revolving shutter
having an opening and connected by gears with G, and
arranged to expose the film during the periods of rest. A
full view of this shutter is also represented, with its opening,
D, in the small illustration to the right.
In practice, the operation would be somewhat as follows,
generally speaking: The lens would first be focussed on the
animate scene to be photographed. On turning the main
shaft of the camera the sprocket, G, is moved intermittently,
and its teeth, catching in the holes in the sensitized film,
draws it downward, bringing a new portion of its length in
front of the lens, the film then remaining stationary for an
instant. In the mean time, through gearing connecting the
main shaft with the shutter, the latter is rotated, bringing
its opening, D, coincident with the lens, and therefore exposing
the film while it is stationary, after which the film again
moves forward. So long as the action is continued these
movements are repeated, resulting in a succession of enormously
rapid exposures upon the film during its progress from
reel H<1S> to its automatic rewinding on reel H<2S>. While the
film is passing through the various parts of the machine it
is guided and kept straight by various sets of rollers between
which it runs, as indicated in the diagram.
By an ingenious arrangement of the mechanism, the film
moves intermittently so that it may have a much longer
period of rest than of motion. As in practice the pictures
are taken at a rate of twenty or more per second, it will be
quite obvious that each period of rest is infinitesimally brief,
being generally one-thirtieth of a second or less. Still it is
sufficient to bring the film to a momentary condition of complete
rest, and to allow for a maximum time of exposure,
comparatively speaking, thus providing means for taking
clearly defined pictures. The negatives so obtained are
developed in the regular way, and the positive prints
subsequently made from them are used for reproduction.
The reproducing machine, or, as it is called in practice, the
Projecting Kinetoscope, is quite similar so far as its general
operations in handling the film are concerned. In appearance
it is somewhat different; indeed, it is in two parts, the
one containing the lighting arrangements and condensing
lens, and the other embracing the mechanism and objective
lens. The "taking" camera must have its parts enclosed
in a light-tight box, because of the undeveloped, sensitized
film, but the projecting kinetoscope, using only a fully developed
positive film, may, and, for purposes of convenient
operation, must be accessibly open. The illustration (Fig. 2)
will show the projecting apparatus as used in practice.
The philosophy of reproduction is very simple, and is illustrated
diagrammatically in Fig. 3, reference letters being the
same as in Fig. 1. As to the additional reference letters, I is
a condenser J the source of light, and K a reflector.
The positive film is moved intermittently but swiftly
throughout its length between the objective lens and a beam
of light coming through the condenser, being exposed by the
shutter during the periods of rest. This results in a pro-
jection of the photographs upon a screen in such rapid succession
as to present an apparently continuous photograph
of the successive positions of the moving objects, which,
therefore, appear to the human eye to be in motion.
The first claim of Reissue Patent No. 12,192 describes the
film. It reads as follows:
"An unbroken transparent or translucent tape-like photographic
film having thereon uniform, sharply defined, equidistant
photographs of successive positions of an object in
motion as observed from a single point of view at rapidly
recurring intervals of time, such photographs being arranged
in a continuous straight-line sequence, unlimited in number
save by the length of the film, and sufficient in number to
represent the movements of the object throughout an extended
period of time."
XVI
EDISON'S ORE-MILLING INVENTIONS
THE wide range of Edison's activities in this department
of the arts is well represented in the diversity of the numerous
patents that have been issued to him from time to
time. These patents are between fifty and sixty in number,
and include magnetic ore separators of ten distinct types; also
breaking, crushing, and grinding
rolls, conveyors, dust-proof bearings,
screens, driers, mixers, bricking
apparatus and machines, ovens,
and processes of various kinds.
A description of the many devices
in each of these divisions
would require more space than is
available; hence, we shall confine
ourselves to a few items of predominating
importance, already referred
to in the narrative. commencing
with the fundamental magnetic ore
separator, which was covered by
United States Patent No. 228,329,
issued June 1, 1880.
The illustration here presented is copied from the drawing forming part of this patent. A hopper
with adjustable feed is supported several feet above a bin having a central partition. Almost
midway between the hopper and the bin is placed an electromagnet whose polar extension is so
arranged as to be a little to one side of a stream of material falling from the hopper. Normally,
a stream of finely divided ore falling from the hopper would fall into that portion of the bin lying
to the left of the partition. If, however, the magnet is energized from a source of current, the
magnetic particles in the falling stream are attracted by and move toward the magnet, which
is so placed with relation to the falling material that the magnetic particles cannot be attracted
entirely to the magnet before gravity has carried them past. Hence, their trajectory
is altered, and they fall on the right-hand side of the
partition in the bin, while the non-magnetic portion of the
stream continues in a straight line and falls on the other
side, thus effecting a complete separation.
This simple but effective principle was the one employed
by Edison in his great concentrating plant already described.
In practice, the numerous hoppers, magnets, and bins were
many feet in length; and they were arranged in batteries of
varied magnetic strength, in order that the intermingled
mass of crushed rock and iron ore might be more thoroughly
separated by being passed through magnetic fields of
successively increasing degrees of attracting power. Altogether
there were about four hundred and eighty of these immense
magnets in the plant, distributed in various buildings in
batteries as above mentioned, the crushed rock containing
the iron ore being delivered to them by conveyors, and the
gangue and ore being taken away after separation by two
other conveyors and delivered elsewhere. The magnetic
separators at first used by Edison at this plant were of the
same generality as the ones employed some years previously
in the separation of sea-shore sand, but greatly enlarged
and improved. The varied experiences gained in the concentration
of vast quantities of ore led naturally to a greater
development, and several new types and arrangements of
magnetic separators were evolved and elaborated by him
from first to last, during the progress of the work at the
concentrating plant.
The magnetic separation of iron from its ore being the
foundation idea of the inventions now under discussion, a
consideration of the separator has naturally taken precedence
over those of collateral but inseparable interest. The ore-
bearing rock, however, must first be ground to powder before
it can be separated; hence, we will now begin at the
root of this operation and consider the "giant rolls," which
Edison devised for breaking huge masses of rock. In his
application for United States Patent No. 672,616, issued
April 23, 1901, applied for on July 16, 1897, he says: "The
object of my invention is to produce a method for the breaking
of rock which will be simple and effective, will not require
the hand-sledging or blasting of the rock down to pieces
of moderate size, and will involve the consumption of a small
amount of power."
While this quotation refers to the method as "simple,"
the patent under consideration covers one of the most bold
and daring projects that Edison has ever evolved. He
proposed to eliminate the slow and expensive method of
breaking large boulders manually, and to substitute therefor
momentum and kinetic energy applied through the medium
of massive machinery, which, in a few seconds, would break
into small pieces a rock as big as an ordinary upright cottage
piano, and weighing as much as six tons. Engineers to
whom Edison communicated his ideas were unanimous in
declaring the thing an impossibility; it was like driving two
express-trains into each other at full speed to crack a great
rock placed between them; that no practical machinery
could be built to stand the terrific impact and strains. Edison's
convictions were strong, however, and he persisted.
The experiments were of heroic size, physically and financially,
but after a struggle of several years and an expenditure
of about $100,000, he realized the correctness and practicability
of his plans in the success of the giant rolls, which
were the outcome of his labors.
The giant rolls consist of a pair of iron cylinders of massive
size and weight, with removable wearing plates having
irregular surfaces formed by projecting knobs. These rolls
are mounted side by side in a very heavy frame (leaving a
gap of about fourteen inches between them), and are so
belted up with the source of power that they run in opposite
directions. The giant rolls described by Edison in the above-
named patent as having been built and operated by him had
a combined weight of 167,000 pounds, including all moving
parts, which of themselves weighed about seventy tons, each
roll being six feet in diameter and five feet long. A top view
of the rolls is shown in the sketch, one roll and one of its
bearings being shown in section.
In Fig. 2 the rolls are illustrated diagrammatically. As
a sketch of this nature, even if given with a definite scale,
does not always carry an adequate idea of relative dimensions
to a non-technical reader, we present in Fig. 3 a perspective
illustration of the giant rolls as installed in the concentrating
plant.
In practice, a small amount of power is applied to run the
giant rolls gradually up to a surface speed of several thousand
feet a minute. When this high speed is attained, masses of
rock weighing several tons in one or more pieces are dumped
into a hopper which guides them into the gap between the
rapidly revolving rolls. The effect is to partially arrest the
swift motion of the rolls instantaneously, and thereby
develop and expend an enormous amount of kinetic energy,
which with pile-driver effect cracks the rocks and breaks
them into pieces small enough to pass through the fourteen-
inch gap. As the power is applied to the rolls through
slipping friction-clutches, the speed of the driving-pulleys
is not materially reduced; hence the rolls may again be
quickly speeded up to their highest velocity while another
load of rock is being hoisted in position to be dumped into
the hopper. It will be obvious from the foregoing that if
it were attempted to supply the great energy necessary for
this operation by direct application of steam-power, an
engine of enormous horse-power would be required, and even
then it is doubtful if one could be constructed of sufficient
strength to withstand the terrific strains that would ensue.
But the work is done by the great momentum and kinetic
energy obtained by speeding up these tremendous masses
of metal, and then suddenly opposing their progress, the
engine being relieved of all strain through the medium of
the slipping friction-clutches. Thus, this cyclopean operation
may be continuously conducted with an amount of
power prodigiously inferior, in proportion, to the results
accomplished.
The sketch (Fig. 4) showing a large boulder being dumped
into the hopper, or roll-pit, will serve to illustrate the method
of feeding these great masses of rock to the rolls, and will
also enable the reader to form an idea of the rapidity of the
breaking operation, when it is stated that a boulder of the
size represented would be reduced by the giant rolls to pieces
a trifle larger than a man's head in a few seconds.
After leaving the giant rolls the broken rock passed on
through other crushing-rolls of somewhat similar construc-
tion. These also were invented by Edison, but antedated
those previously described; being covered by Patent No.
567,187, issued September 8, 1896. These rolls were
intended for the reducing of "one-man-size" rocks to small
pieces, which at the time of their original inception was
about the standard size of similar machines. At the
Edison concentrating plant the broken rock, after passing
through these rolls, was further reduced in size by other rolls,
and was then ready to be crushed to a fine powder through
the medium of another remarkable machine devised by
NOTE.--Figs. 3 and 4 are reproduced from similar sketches on pages 84 and 85
of McClure's Magazine for November, 1897, by permission of S. S. McClure Co.
Edison to meet his ever-recurring and well-defined ideas of
the utmost economy and efficiency. The best fine grinding-
machines that it was then possible to obtain were so
inefficient as to involve a loss of 82 per cent. of the power
applied. The thought of such an enormous loss was unbearable,
and he did not rest until he had invented and put into
use an entirely new grinding-machine, which was called the
"three-high" rolls. The device was covered by a patent
issued to him on November 21, 1899, No. 637,327. It was
a most noteworthy invention, for it brought into the art
not only a greater efficiency of grinding than had ever been
dreamed of before, but also a tremendous economy by the
saving of power; for whereas the previous efficiency had
been 18 per cent. and the loss 82 per cent., Edison reversed
these figures, and in his three-high rolls produced a working
efficiency of 84 per cent., thus reducing the loss of power
by friction to 16 per cent. A diagrammatic sketch of this
remarkable machine is shown in Fig. 5, which shows a front
elevation with the casings, hopper, etc., removed, and also
shows above the rolls the rope and pulleys, the supports for
which are also removed for the sake of clearness in the
illustration.
For the convenience of the reader, in referring to Fig. 5,
we will repeat the description of the three-high rolls, which
is given on pages 487 and 488 of the preceding narrative.
In the two end-pieces of a heavy iron frame were set three
rolls, or cylinders--one in the centre, another below, and
the other above--all three being in a vertical line. These
rolls were about three feet in diameter, made of cast-iron,
and had face-plates of chilled-iron.[31] The lowest roll was set
in a fixed bearing at the bottom of the frame, and, therefore,
could only turn around on its axis. The middle and top
rolls were free to move up or down from and toward the
lower roll, and the shafts of the middle and upper rolls were
set in a loose bearing which could slip up and down in the
iron frame. It will be apparent, therefore, that any material
which passed in between the top and the middle rolls,
and the middle and bottom rolls, could be ground as fine as
might be desired, depending entirely upon the amount of
pressure applied to the loose rolls. In operation the material
passed first through the upper and middle rolls, and then
between the middle and lowest rolls.
[31] The faces of these rolls were smooth, but as three-high rolls
came into use later in Edison's Portland cement operations the faces
were corrugated so as to fit into each other, gear-fashion, to provide
for a high rate of feed.
This pressure was applied in a most ingenious manner.
On the ends of the shafts of the bottom and top rolls there
were cylindrical sleeves, or bearings, having seven sheaves
in which was run a half-inch endless wire rope. This rope
was wound seven times over the sheaves as above, and led
upward and over a single-groove sheave, which was operated
by the piston of an air-cylinder, and in this manner the
pressure was applied to the rolls. It will be seen, therefore
that the system consisted in a single rope passed over sheaves
and so arranged that it could be varied in length, thus providing
for elasticity in exerting pressure and regulating it
as desired. The efficiency of this system was incomparably
greater than that of any other known crusher or grinder, for
while a pressure of one hundred and twenty-five thousand
pounds could be exerted by these rolls, friction was almost
entirely eliminated, because the upper and lower roll bearings
turned with the rolls and revolved in the wire rope,
which constituted the bearing proper.
Several other important patents have been issued to Edison
for crushing and grinding rolls, some of them being for
elaborations and improvements of those above described
but all covering methods of greater economy and effectiveness
in rock-grinding.
Edison's work on conveyors during the period of his ore-
concentrating labors was distinctively original, ingenious
and far in advance of the times. His conception of the
concentrating problem was broad and embraced an entire
system, of which a principal item was the continuous transfer
of enormous quantities of material from place to place
at the lowest possible cost. As he contemplated the concentration
of six thousand tons daily, the expense of manual
labor to move such an immense quantity of rock, sand, and
ore would be absolutely prohibitive. Hence, it became
necessary to invent a system of conveyors that would be
capable of transferring this mass of material from one place
to another. And not only must these conveyors be capable
of carrying the material, but they must also be devised so
that they would automatically receive and discharge their
respective loads at appointed places. Edison's ingenuity,
engineering ability, and inventive skill were equal to the task,
however, and were displayed in a system and variety of conveyors
that in practice seemed to act with almost human
discrimination. When fully installed throughout the plant,
they automatically transferred daily a mass of material equal
to about one hundred thousand cubic feet, from mill to mill,
covering about a mile in the transit. Up and down, winding
in and out, turning corners, delivering material from one to
another, making a number of loops in the drying-oven, filling
up bins and passing on to the next when they were full,
these conveyors in automatic action seemingly played their
part with human intelligence, which was in reality the reflection
of the intelligence and ingenuity that had originally
devised them and set them in motion.
Six of Edison's patents on conveyors include a variety
of devices that have since came into broad general use for
similar work, and have been the means of effecting great
economies in numerous industries of widely varying kinds.
Interesting as they are, however, we shall not attempt to
describe them in detail, as the space required would be too
great. They are specified in the list of patents following this
Appendix, and may be examined in detail by any interested
student.
In the same list will also be found a large number of Edison's
patents on apparatus and methods of screening, drying,
mixing, and briquetting, as well as for dust-proof
bearings, and various types and groupings of separators,
all of which were called forth by the exigencies and magnitude
of his great undertaking, and without which he could
not possibly have attained the successful physical results
that crowned his labors. Edison's persistence in reducing
the cost of his operations is noteworthy in connection with
his screening and drying inventions, in which the utmost
advantage is taken of the law of gravitation. With its
assistance, which cost nothing, these operations were
performed perfectly. It was only necessary to deliver the
material at the top of the chambers, and during its natural
descent it was screened or dried as the case might be.
All these inventions and devices, as well as those described
in detail above (except magnetic separators and mixing
and briquetting machines), are being used by him to-day
in the manufacture of Portland cement, as that industry
presents many of the identical problems which presented
themselves in relation to the concentration of iron ore.
XVII
THE LONG CEMENT KILN
IN this remarkable invention, which has brought about a
striking innovation in a long-established business, we see
another characteristic instance of Edison's incisive reasoning
and boldness of conception carried into practical effect
in face of universal opinions to the contrary.
For the information of those unacquainted with the process
of manufacturing Portland cement, it may be stated
that the material consists preliminarily of an intimate mixture
of cement rock and limestone, ground to a very fine
powder. This powder is technically known in the trade as
"chalk," and is fed into rotary kilns and "burned"; that is
to say, it is subjected to a high degree of heat obtained by
the combustion of pulverized coal, which is injected into the
interior of the kiln. This combustion effects a chemical
decomposition of the chalk, and causes it to assume a plastic
consistency and to collect together in the form of small
spherical balls. which are known as "clinker." Kilns are
usually arranged with a slight incline, at the upper end of
which the chalk is fed in and gradually works its way down
to the interior flame of burning fuel at the other end. When
it arrives at the lower end, the material has been "burned,"
and the clinker drops out into a receiving chamber below.
The operation is continuous, a constant supply of chalk
passing in at one end of the kiln and a continuous dribble of
clinker-balls dropping out at the other. After cooling, the
clinker is ground into very fine powder, which is the Portland
cement of commerce.
It is self-evident that an ideal kiln would be one that
produced the maximum quantity of thoroughly clinkered
material with a minimum amount of fuel, labor, and investment.
When Edison was preparing to go into the cement
business, he looked the ground over thoroughly, and, after
considerable investigation and experiment, came to the conclusion
that prevailing conditions as to kilns were far from
ideal.
The standard kilns then in use were about sixty feet in
length, with an internal diameter of about five feet. In all
rotary kilns for burning cement, the true clinkering operation
takes place only within a limited portion of their total
length, where the heat is greatest; hence the interior of the
kiln may be considered as being divided longitudinally into
two parts or zones--namely, the combustion, or clinkering,
zone, and the zone of oncoming raw material. In the sixty-
foot kiln the length of the combustion zone was about ten
feet, extending from a point six or eight feet from the lower,
or discharge, end to a point about eighteen feet from that
end. Consequently, beyond that point there was a zone of
only about forty feet, through which the heated gases passed
and came in contact with the oncoming material, which was
in movement down toward the clinkering zone. Since the
bulk of oncoming material was small, the gases were not
called upon to part with much of their heat, and therefore
passed on up the stack at very high temperatures, ranging
from 1500 degrees to 1800 degrees Fahr. Obviously, this heat was entirely
lost.
An additional loss of efficiency arose from the fact that
the material moved so rapidly toward the combustion zone
that it had not given up all its carbon dioxide on reaching
there; and by the giving off of large quantities of that gas
within the combustion zone, perfect and economical combustion
of coal could not be effected.
The comparatively short length of the sixty-foot kiln not
only limited the amount of material that could be fed into
it, but the limitation in length of the combustion zone militated
against a thorough clinkering of the material, this
operation being one in which the elements of time and proper
heat are prime considerations. Thus the quantity of good
clinker obtainable was unfavorably affected. By reason of
these and other limitations and losses, it had been possible,
in practice, to obtain only about two hundred and fifty
barrels of clinker per day of twenty-four hours; and that
with an expenditure for coal proportionately equal to about
29 to 33 per cent. of the quantity of clinker produced, even
assuming that all the clinker was of good quality.
Edison realized that the secret of greater commercial
efficiency and improvement of quality lay in the ability to
handle larger quantities of material within a given time, and
to produce a more perfect product without increasing cost
or investment in proportion. His reasoning led him to the
conclusion that this result could only be obtained through
the use of a kiln of comparatively great length, and his
investigations and experiments enabled him to decide upon
a length of one hundred and fifty feet, but with an increase
in diameter of only six inches to a foot over that of the sixty-
foot kiln.
The principal considerations that influenced Edison in
making this radical innovation may be briefly stated as
follows:
First. The ability to maintain in the kiln a load from five
to seven times greater than ordinarily employed, thereby
tending to a more economical output.
Second. The combustion of a vastly increased bulk of
pulverized coal and a greatly enlarged combustion zone,
extending about forty feet longitudinally into the kiln--thus
providing an area within which the material might be maintained
in a clinkering temperature for a sufficiently long
period to insure its being thoroughly clinkered from periphery
to centre.
Third. By reason of such a greatly extended length of the
zone of oncoming material (and consequently much greater
bulk), the gases and other products of combustion would be
cooled sufficiently between the combustion zone and the stack
so as to leave the kiln at a comparatively low temperature.
Besides, the oncoming material would thus be gradually
raised in temperature instead of being heated abruptly, as
in the shorter kilns.
Fourth. The material having thus been greatly raised in
temperature before reaching the combustion zone would
have parted with substantially all its carbon dioxide, and
therefore would not introduce into the combustion zone
sufficient of that gas to disturb the perfect character of the
combustion.
Fifth. On account of the great weight of the heavy load
in a long kiln, there would result the formation of a continuous
plastic coating on that portion of the inner surface
of the kiln where temperatures are highest. This would
effectively protect the fire-brick lining from the destructive
effects of the heat.
Such, in brief, were the essential principles upon which
Edison based his conception and invention of the long kiln,
which has since become so well known in the cement business.
Many other considerations of a minor and mechanical
nature, but which were important factors in his solution of
this difficult problem, are worthy of study by those intimately
associated with or interested in the art. Not the least
of the mechanical questions was settled by Edison's decision
to make this tremendously long kiln in sections of cast-iron,
with flanges, bolted together, and supported on rollers
rotated by electric motors. Longitudinal expansion and
thrust were also important factors to be provided for, as
well as special devices to prevent the packing of the mass
of material as it passed in and out of the kiln. Special
provision was also made for injecting streams of pulverized coal
in such manner as to create the largely extended zone of
combustion. As to the details of these and many other in-
genious devices, we must refer the curious reader to the
patents, as it is merely intended in these pages to indicate
in a brief manner the main principles of Edison's notable
inventions. The principal United States patent on the long
kiln was issued October 24, 1905, No. 802,631.
That his reasonings and deductions were correct in this
case have been indubitably proven by some years of experience
with the long kiln in its ability to produce from
eight hundred to one thousand barrels of good clinker every
twenty-four hours, with an expenditure for coal proportionately
equal to about only 20 per cent. of the quantity of
clinker produced.
To illustrate the long cement kiln by diagram would convey
but little to the lay mind, and we therefore present an
illustration (Fig. 1) of actual kilns in perspective, from which
sense of their proportions may be gathered.
XVIII
EDISON'S NEW STORAGE BATTERY
GENERICALLY considered, a "battery" is a device which
generates electric current. There are two distinct species
of battery, one being known as "primary," and the other
as "storage," although the latter is sometimes referred to
as a "secondary battery" or "accumulator." Every type
of each of these two species is essentially alike in its general
make-up; that is to say, every cell of battery of any kind
contains at least two elements of different nature immersed
in a more or less liquid electrolyte of chemical character.
On closing the circuit of a primary battery an electric current
is generated by reason of the chemical action which is
set up between the electrolyte and the elements. This involves
a gradual consumption of one of the elements and a
corresponding exhaustion of the active properties of the
electrolyte. By reason of this, both the element and the
electrolyte that have been used up must be renewed from
time to time, in order to obtain a continued supply of electric
current.
The storage battery also generates electric current through
chemical action, but without involving the constant repriming
with active materials to replace those consumed and
exhausted as above mentioned. The term "storage," as
applied to this species of battery, is, however, a misnomer,
and has been the cause of much misunderstanding to nontechnical
persons. To the lay mind a "storage" battery
presents itself in the aspect of a device in which electric
energy is STORED, just as compressed air is stored or accumulated
in a tank. This view, however, is not in accordance
with facts. It is exactly like the primary battery in the
fundamental circumstance that its ability for generating
electric current depends upon chemical action. In strict
terminology it is a "reversible" battery, as will be quite obvious
if we glance briefly at its philosophy. When a storage
battery is "charged," by having an electric current passed
through it, the electric energy produces a chemical effect,
adding oxygen to the positive plate, and taking oxygen away
from the negative plate. Thus, the positive plate becomes
oxidized, and the negative plate reduced. After the charging
operation is concluded the battery is ready for use, and
upon its circuit being closed through a translating device,
such as a lamp or motor, a reversion ("discharge") takes
place, the positive plate giving up its oxygen, and the negative
plate being oxidized. These chemical actions result in
the generation of an electric current as in a primary battery.
As a matter of fact, the chemical actions and reactions
in a storage battery are much more complex, but the
above will serve to afford the lay reader a rather simple idea
of the general result arrived at through the chemical activity
referred to.
The storage battery, as a commercial article, was introduced
into the market in the year 1881. At that time, and
all through the succeeding years, until about 1905, there
was only one type that was recognized as commercially
practicable--namely, that known as the lead-sulphuric-acid
cell, consisting of lead plates immersed in an electrolyte of
dilute sulphuric acid. In the year last named Edison first
brought out his new form of nickel-iron cell with alkaline
electrolyte, as we have related in the preceding narrative.
Early in the eighties, at Menlo Park, he had given much
thought to the lead type of storage battery, and during the
course of three years had made a prodigious number of experiments
in the direction of improving it, probably performing
more experiments in that time than the aggregate
of those of all other investigators. Even in those early days
he arrived at the conclusion that the lead-sulphuric-acid
combination was intrinsically wrong, and did not embrace
the elements of a permanent commercial device. He did
not at that time, however, engage in a serious search for
another form of storage battery, being tremendously occupied
with his lighting system and other matters.
It may here be noted, for the information of the lay
reader, that the lead-acid type of storage battery consists
of two or more lead plates immersed in dilute sulphuric acid
and contained in a receptacle of glass, hard rubber, or other
special material not acted upon by acid. The plates are
prepared and "formed" in various ways, and the chemical
actions are similar to those above stated, the positive plate
being oxidized and the negative reduced during "charge,"
and reversed during "discharge." This type of cell, however,
has many serious disadvantages inherent to its very
nature. We will name a few of them briefly. Constant
dropping of fine particles of active material often causes
short-circuiting of the plates, and always necessitates occasional
washing out of cells; deterioration through "sulphation"
if discharge is continued too far or if recharging is not
commenced quickly enough; destruction of adjacent metal-
work by the corrosive fumes given out during charge and
discharge; the tendency of lead plates to "buckle" under
certain conditions; the limitation to the use of glass, hard
rubber, or similar containers on account of the action of the
acid; and the immense weight for electrical capacity. The
tremendously complex nature of the chemical reactions which
take place in the lead-acid storage battery also renders it an
easy prey to many troublesome diseases.
In the year 1900, when Edison undertook to invent a
storage battery, he declared it should be a new type into
which neither sulphuric nor any other acid should enter.
He said that the intimate and continued companionship of
an acid and a metal was unnatural, and incompatible with
the idea of durability and simplicity. He furthermore
stated that lead was an unmechanical metal for a battery,
being heavy and lacking stability and elasticity, and that
as most metals were unaffected by alkaline solutions, he
was going to experiment in that direction. The soundness
of his reasoning is amply justified by the perfection of results
obtained in the new type of storage battery bearing his
name, and now to be described.
The essential technical details of this battery are fully
described in an article written by one of Edison's laboratory
staff, Walter E. Holland, who for many years has been
closely identified with the inventor's work on this cell
The article was published in the Electrical World, New
York, April 28, 1910; and the following extracts there-
from will afford an intelligent comprehension of this invention:
"The `A' type Edison cell is the outcome of nine years of
costly experimentation and persistent toil on the part of its
inventor and his associates....
"The Edison invention involves the use of an entirely new
voltaic combination in an alkaline electrolyte, in place of the
lead-lead-peroxide combination and acid electrolyte, characteristic
of all other commercial storage batteries. Experience
has proven that this not only secures durability and
greater output per unit-weight of battery, but in addition
there is eliminated a long list of troubles and diseases inherent
in the lead-acid combination....
"The principle on which the action of this new battery is
based is the oxidation and reduction of metals in an electrolyte
which does not combine with, and will not dissolve,
either the metals or their oxides; and an electrolyte, furthermore,
which, although decomposed by the action of the
battery, is immediately re-formed in equal quantity; and
therefore in effect is a CONSTANT element, not changing in density
or in conductivity.
"A battery embodying this basic principle will have features
of great value where lightness and durability are desiderata.
For instance, the electrolyte, being a constant
factor, as explained, is not required in any fixed and large
amount, as is the case with sulphuric acid in the lead battery;
thus the cell may be designed with minimum distancing of
plates and with the greatest economy of space that is consistent
with safe insulation and good mechanical design.
Again, the active materials of the electrodes being insoluble
in, and absolutely unaffected by, the electrolyte, are not liable
to any sort of chemical deterioration by action of the
electrolyte--no matter how long continued....
"The electrolyte of the Edison battery is a 21 per cent.
solution of potassium hydrate having, in addition, a small
amount of lithium hydrate. The active metals of the electrodes
--which will oxidize and reduce in this electrolyte
without dissolution or chemical deterioration--are nickel
and iron. These active elements are not put in the plates
AS METALS; but one, nickel, in the form of a hydrate, and the
other, iron, as an oxide.
"The containing cases of both kinds of active material
(Fig. 1), and their supporting grids (Fig. 2), as well as the
bolts, washers, and nuts used in assembling (Fig. 3), and
even the retaining can and its cover (Fig. 4), are all made of
nickel-plated steel--a material in which lightness, durability
and mechanical strength are most happily combined, and a
material beyond suspicion as to corrosion in an alkaline
electrolyte....
"An essential part of Edison's discovery of active ma-
setials for an alkaline storage battery was the PREPARATION
of these materials. Metallic powder of iron and nickel, or
even oxides of these metals, prepared in the ordinary way,
are not chemically active in a sufficient degree to work in a
battery. It is only when specially prepared iron oxide of
exceeding fineness, and nickel hydrate conforming to certain
physical, as well as chemical, standards can be made that the
alkaline battery is practicable. Needless to say, the working
out of the conditions and processes of manufacture of the
materials has involved great ingenuity and endless experimentation."
The article then treats of Edison's investigations into
means for supporting and making electrical connection with
the active materials, showing some of the difficulties encountered
and the various discoveries made in developing the perfected
cell, after which the writer continues his description
of the "A" type cell, as follows:
"It will be seen at once that the construction of the two
kinds of plate is radically different. The negative or iron
plate (Fig. 5) has the familiar flat-pocket construction.
Each negative contains twenty-four pockets--a pocket being
1/2 inch wide by 3 inches long, and having a maximum thickness
of a little more than 1/8 inch. The positive or nickel
plate (Fig. 6) is seen to consist of two rows of round rods
or pencils, thirty in number, held in a vertical position by
a steel support-frame. The pencils have flat flanges at the
ends (formed by closing in the metal case), by which they
are supported and electrical connection is made. The frame
is slit at the inner horizontal edges, and then folded in such
a way as to make individual clamping-jaws for each end-
flange. The clamping-in is done at great pressure, and the
resultant plate has great rigidity and strength.
"The perforated tubes into which the nickel active material
is loaded are made of nickel-plated steel of high quality.
They are put together with a double-lapped spiral seam to
give expansion-resisting qualities, and as an additional
precaution small metal rings are slipped on the outside. Each
tube is 1/4 inch in diameter by 4 1/8 inches long, add has eight
of the reinforcing rings.
"It will be seen that the `A' positive plate has been given
the theoretically best design to prevent expansion and overcome
trouble from that cause. Actual tests, long continued
under very severe conditions, have shown that the construction
is right, and fulfils the most sanguine expectations."
Mr. Holland in his article then goes on to explain the
development of the nickel flakes as the conducting factor in
the positive element, but as this has already been described
in Chapter XXII, we shall pass on to a later point, where
he says:
"An idea of the conditions inside a loaded tube can best
be had by microscopic examination. Fig. 7 shows a magnified
section of a regularly loaded tube which has been
sawed lengthwise. The vertical bounding walls are edges
of the perforated metal containing tube; the dark horizontal
lines are layers of nickel flake, while the light-colored
thicker layers represent the nickel hydrate. It should be
noted that the layers of flake nickel extend practically
unbroken across the tube and make contact with the metal wall
at both sides. These metal layers conduct current to or from
the active nickel hydrate in all parts of the tube very
efficiently. There are about three hundred and fifty layers of
each kind of material in a 4 1/8 -inch tube, each layer of nickel
hydrate being about 0.01 inch thick; so it will be seen that
the current does not have to penetrate very far into the nickel
hydrate--one-half a layer's thickness being the maximum
distance. The perforations of the containing tube, through
which the electrolyte reaches the active material, are also
shown in Fig. 7."
In conclusion, the article enumerates the chief
characteristics of the Edison storage battery which fit it pre-
eminently for transportation service, as follows: 1. No
loss of active material, hence no sediment short-circuits.
2. No jar breakage. 3. Possibility of quick disconnection
or replacement of any cell without employment of skilled
labor. 4. Impossibility of "buckling" and harmlessness of
a dead short-circuit. 5. Simplicity of care required. 6.
Durability of materials and construction. 7. Impossibility
of "sulphation." 8. Entire absence of corrosive fumes.
9. Commercial advantages of light weight. 10. Duration
on account of its dependability. 11. Its high practical
efficiency.
XIX
EDISON'S POURED CEMENT HOUSE
THE inventions that have been thus far described fall into
two classes--first, those that were fundamental in the great
arts and industries which have been founded and established
upon them, and, second, those that have entered into
and enlarged other arts that were previously in existence.
On coming to consider the subject now under discussion,
however, we find ourselves, at this writing, on the threshold
of an entirely new and undeveloped art of such boundless
possibilities that its ultimate extent can only be a matter of
conjecture.
Edison's concrete house, however, involves two main
considerations, first of which was the conception or creation of
the IDEA--vast and comprehensive--of providing imperishable
and sanitary homes for the wage-earner by molding
an entire house in one piece in a single operation, so to speak,
and so simply that extensive groups of such dwellings could
be constructed rapidly and at very reasonable cost. With
this idea suggested, one might suppose that it would be a
simple matter to make molds and pour in a concrete mixture.
Not so, however. And here the second consideration
presents itself. An ordinary cement mixture is composed
of crushed stone, sand, cement, and water. If such a mixture
be poured into deep molds the heavy stone and sand
settle to the bottom. Should the mixture be poured into
a horizontal mold, like the floor of a house, the stone and
sand settle, forming an ununiform mass. It was at this
point that invention commenced, in order to produce a concrete
mixture which would overcome this crucial difficulty.
Edison, with characteristic thoroughness, took up a line of
investigation, and after a prolonged series of experiments
succeeded in inventing a mixture that upon hardening re-
mained uniform throughout its mass. In the beginning of
his experimentation he had made the conditions of test
very severe by the construction of forms similar to that
shown in the sketch below.
This consisted of a hollow wooden form of the dimensions
indicated. The mixture was to be poured into the hopper
until the entire form was filled, such mixture flowing down
and along the horizontal legs and up the vertical members.
It was to be left until the mixture was hard, and the requirement
of the test was that there should be absolute uniformity
of mixture and mass throughout. This was finally
accomplished, and further invention then proceeded along
engineering lines looking toward the devising of a system
of molds with which practicable dwellings might be cast.
Edison's boldness and breadth of conception are well illustrated
in his idea of a poured house, in which he displays his
accustomed tendency to reverse accepted methods. In fact,
it is this very reversal of usual procedure that renders it
difficult for the average mind to instantly grasp the full
significance of the principles involved and the results attained.
Up to this time we have been accustomed to see the erection
of a house begun at the foundation and built up slowly,
piece by piece, of solid materials: first the outer frame, then
the floors and inner walls, followed by the stairways, and
so on up to the putting on of the roof. Hence, it requires a
complete rearrangement of mental conceptions to appreciate
Edison's proposal to build a house FROM THE TOP DOWNWARD,
in a few hours, with a freely flowing material poured into
molds, and in a few days to take away the molds and find
a complete indestructible sanitary house, including foundation,
frame, floors, walls, stairways, chimneys, sanitary
arrangements, and roof, with artistic ornamentation inside and
out, all in one solid piece, as if it were graven or bored out
of a rock.
To bring about the accomplishment of a project so extraordinarily
broad involves engineering and mechanical conceptions
of a high order, and, as we have seen, these have
been brought to bear on the subject by Edison, together with
an intimate knowledge of compounded materials.
The main features of this invention are easily comprehensible
with the aid of the following diagrammatic sectional sketch:
It should be first understood that the above sketch is in
broad outline, without elaboration, merely to illustrate the
working principle; and while the upright structure on the
right is intended to represent a set of molds in position to
form a three-story house, with cellar, no regular details of
such a building (such as windows, doors, stairways, etc.) are
here shown, as they would only tend to complicate an
explanation.
It will be noted that there are really two sets of molds,
an inside and an outside set, leaving a space between them
throughout. Although not shown in the sketch, there is in
practice a number of bolts passing through these two sets
of molds at various places to hold them together in their
relative positions. In the open space between the molds
there are placed steel rods for the purpose of reinforcement;
while all through the entire structure provision is made for
water and steam pipes, gas-pipes and electric-light wires
being placed in appropriate positions as the molds are
assembled.
At the centre of the roof there will be noted a funnel-
shaped opening. Into this there is delivered by the endless
chain of buckets shown on the left a continuous stream of
a special free-flowing concrete mixture. This mixture descends
by gravity, and gradually fills the entire space between
the two sets of molds. The delivery of the material--or
"pouring," as it is called--is continued until every part of
the space is filled and the mixture is even with the tip of
the roof, thus completing the pouring, or casting, of the
house. In a few days afterward the concrete will have
hardened sufficiently to allow the molds to be taken away
leaving an entire house, from cellar floor to the peak of the
roof, complete in all its parts, even to mantels and picture
molding, and requiring only windows and doors, plumbing,
heating, and lighting fixtures to make it ready for habitation.
In the above sketch the concrete mixers, A, B, are driven
by the electric motor, C. As the material is mixed it descends
into the tank, D, and flows through a trough into a lower
tank, E, in which it is constantly stirred, and from which it
is taken by the endless chain of buckets and dumped into
the funnel-shaped opening at the top of the molds, as above
described.
The molds are made of cast-iron in sections of such size
and weight as will be most convenient for handling, mostly
in pieces not exceeding two by four feet in rectangular
dimensions. The subjoined sketch shows an exterior view of
several of these molds as they appear when bolted together,
the intersecting central portions representing ribs, which are
included as part of the casting for purposes of strength and
rigidity.
The molds represented above are those for straight work,
such as walls and floors. Those intended for stairways,
eaves, cornices, windows, doorways, etc., are much more
complicated in design, although the same general principles
are employed in their construction.
While the philosophy of pouring or casting a complete
house in its entirety is apparently quite simple, the development
of the engineering and mechanical questions involves
the solution of a vast number of most intricate and complicated
problems covering not only the building as a whole,
but its numerous parts, down to the minutest detail. Safety,
convenience, duration, and the practical impossibility of
altering a one-piece solid dwelling are questions that must
be met before its construction, and therefore Edison has
proceeded calmly on his way toward the goal he has ever had
clearly in mind, with utter indifference to the criticisms and
jeers of those who, as "experts," have professed positive
knowledge of the impossibility of his carrying out this daring
scheme.
LIST OF UNITED STATES PATENTS
List of United States patents granted to Thomas A. Edison,
arranged according to dates of execution of
applications for such patents. This list shows
the inventions as Mr. Edison has worked
upon them from year to year
1868
NO. TITLE OF PATENT DATE EXECUTED DATE EXECUTED
90,646, Electrographic Vote Recorder . . . . .Oct. 13, 1868
1869
91,527 Printing Telegraph (reissued October
25, 1870, numbered 4166, and August
5, 1873, numbered 5519). . . . . . . .Jan. 25, 1869
96,567 Apparatus for Printing Telegraph (reissued
February 1, 1870, numbered
3820). . . . . . . . . . . . . . . . .Aug. 17, 1869
96,681 Electrical Switch for Telegraph ApparatusAug. 27, 1869
102,320 Printing Telegraph--Pope and Edison
(reissued April 17, 1877, numbered
7621, and December 9, 1884, numbered
10,542). . . . . . . . . . . . . . . Sept. 16, 1869
103,924 Printing Telegraphs--Pope and Edison
(reissued August 5, 1873)
1870
103,035 Electromotor Escapement. . . . . . . . Feb. 5, 1870
128,608 Printing Telegraph Instruments . . . . .May 4, 1870
114,656 Telegraph Transmitting Instruments . .June 22, 1870
114,658 Electro Magnets for Telegraph
Instruments. . . . . . . . . . . . . .June 22, 1870
114,657 Relay Magnets for Telegraph
Instruments. . . . . . . . . . . . . .Sept. 6, 1870
111,112 Electric Motor Governors . . . . . . .June 29, 1870
113,033 Printing Telegraph Apparatus . . . . .Nov. 17, 1870
1871
113,034 Printing Telegraph Apparatus . . . . .Jan. 10, 1871
123,005 Telegraph Apparatus. . . . . . . . . .July 26, 1871
123,006 Printing Telegraph . . . . . . . . . .July 26, 1871
123,984 Telegraph Apparatus. . . . . . . . . .July 26, 1871
124,800 Telegraphic Recording Instruments. . .Aug. 12, 1871
121,601 Machinery for Perforating Paper for
Telegraph Purposes . . . . . . . . . .Aug. 16, 1871
126,535 Printing Telegraphs. . . . . . . . . .Nov. 13, 1871
133,841 Typewriting Machine. . . . . . . . . .Nov. 13, 1871
1872
126,532 Printing Telegraphs. . . . . . . . . . .Jan. 3 1872
126,531 Printing Telegraphs. . . . . . . . . .Jan. 17, 1872
126,534 Printing Telegraphs. . . . . . . . . .Jan. 17, 1872
126,528 Type Wheels for Printing Telegraphs. .Jan. 23, 1872
126,529 Type Wheels for Printing Telegraphs. .Jan. 23, 1872
126,530 Printing Telegraphs. . . . . . . . . .Feb. 14, 1872
126,533 Printing Telegraphs. . . . . . . . . .Feb. 14, 1872
132,456 Apparatus for Perforating Paper for
Telegraphic Use. . . . . . . . . . . March 15, 1872
132,455 Improvement in Paper for Chemical
Telegraphs . . . . . . . . . . . . . April 10, 1872
133,019 Electrical Printing Machine. . . . . April 18, 1872
128,131 Printing Telegraphs. . . . . . . . . April 26, 1872
128,604 Printing Telegraphs. . . . . . . . . April 26, 1872
128,605 Printing Telegraphs. . . . . . . . . April 26, 1872
128,606 Printing Telegraphs. . . . . . . . . April 26, 1872
128,607 Printing Telegraphs. . . . . . . . . April 26, 1872
131,334 Rheotomes or Circuit Directors . . . . .May 6, 1872
134,867 Automatic Telegraph Instruments. . . . .May 8, 1872
134,868 Electro Magnetic Adjusters . . . . . . .May 8, 1872
130,795 Electro Magnets. . . . . . . . . . . . .May 9, 1872
131,342 Printing Telegraphs. . . . . . . . . . .May 9, 1872
131,341 Printing Telegraphs. . . . . . . . . . May 28, 1872
131,337 Printing Telegraphs. . . . . . . . . .June 10, 1872
131,340 Printing Telegraphs. . . . . . . . . .June 10, 1872
131,343 Transmitters and Circuits for Printing
Telegraph. . . . . . . . . . . . . . .June 10, 1872
131,335 Printing Telegraphs. . . . . . . . . .June 15, 1872
131,336 Printing Telegraphs. . . . . . . . . .June 15, 1872
131,338 Printing Telegraphs. . . . . . . . . .June 29, 1872
131,339 Printing Telegraphs. . . . . . . . . .June 29, 1872
131,344 Unison Stops for Printing Telegraphs .June 29, 1872
134,866 Printing and Telegraph Instruments . .Oct. 16, 1872
138,869 Printing Telegraphs. . . . . . . . . .Oct. 16, 1872
142,999 Galvanic Batteries . . . . . . . . . .Oct. 31, 1872
141,772 Automatic or Chemical Telegraphs . . . Nov. 5, 1872
135,531 Circuits for Chemical Telegraphs . . . Nov. 9, 1872
146,812 Telegraph Signal Boxes . . . . . . . .Nov. 26, 1872
141,773 Circuits for Automatic Telegraphs. . .Dec. 12, 1872
141,776 Circuits for Automatic Telegraphs. . .Dec. 12, 1872
150,848 Chemical or Automatic Telegraphs . . .Dec. 12, 1872
1873
139,128 Printing Telegraphs. . . . . . . . . .Jan. 21, 1873
139,129 Printing Telegraphs. . . . . . . . . .Feb. 13, 1873
140,487 Printing Telegraphs. . . . . . . . . .Feb. 13, 1873
140,489 Printing Telegraphs. . . . . . . . . .Feb. 13, 1873
138,870 Printing Telegraphs. . . . . . . . . .March 7, 1873
141,774 Chemical Telegraphs. . . . . . . . . .March 7, 1873
141,775 Perforator for Automatic Telegraphs. .March 7, 1873
141,777 Relay Magnets. . . . . . . . . . . . .March 7, 1873
142,688 Electric Regulators for Transmitting
Instruments . . . . . . . . . . . . . .March 7, 1873
156,843 Duplex Chemical Telegraphs . . . . . .March 7, 1873
147,312 Perforators for Automatic Telegraphy March 24, 1873
147,314 Circuits for Chemical Telegraphs . . March 24, 1873
150,847 Receiving Instruments for Chemical
Telegraphs . . . . . . . . . . . . . March 24, 1873
140,488 Printing Telegraphs. . . . . . . . . April 23, 1873
147,311 Electric Telegraphs. . . . . . . . . April 23, 1873
147,313 Chemical Telegraphs. . . . . . . . . April 23, 1873
147,917 Duplex Telegraphs. . . . . . . . . . April 23, 1873
150,846 Telegraph Relays . . . . . . . . . . April 23, 1873
160,405 Adjustable Electro Magnets for
Relays, etc. . . . . . . . . . . . . April 23, 1873
162,633 Duplex Telegraphs. . . . . . . . . . April 22, 1873
151,209 Automatic Telegraphy and Perforators
Therefor . . . . . . . . . . . . . . .Aug. 25, 1873
160,402 Solutions for Chemical Telegraph PaperSept. 29, 1873
160,404 Solutions for Chemical Telegraph PaperSept. 29, 1873
160,580 Solutions for Chemical Telegraph PaperOct. 14, 1873
160,403 Solutions for Chemical Telegraph PaperOct. 29, 1873
1874
154,788 District Telegraph Signal Box. . . . .April 2, 1874
168,004 Printing Telegraph . . . . . . . . . . May 22, 1874
166,859 Chemical Telegraphy. . . . . . . . . . June 1, 1874
166,860 Chemical Telegraphy. . . . . . . . . . June 1, 1874
166,861 Chemical Telegraphy. . . . . . . . . . June 1, 1874
158,787 Telegraph Apparatus. . . . . . . . . . Aug. 7, 1874
172,305 Automatic Roman Character
Telegraph. . . . . . . . . . . . . . . Aug. 7, 1874
173,718 Automatic Telegraphy . . . . . . . . . Aug. 7, 1874
178,221 Duplex Telegraphs. . . . . . . . Aug. 19, 1874
178,222 Duplex Telegraphs. . . . . . . . . . .Aug. 19, 1874
178,223 Duplex Telegraphs. . . . . . . . . . .Aug. 19, 1874
180,858 Duplex Telegraphs. . . . . . . . . . .Aug. 19, 1874
207,723 Duplex Telegraphs. . . . . . . . . . .Aug. 19, 1874
480,567 Duplex Telegraphs. . . . . . . . . . .Aug. 19, 1874
207,724 Duplex Telegraphs. . . . . . . . . . .Dec. 14, 1874
1875
168,242 Transmitter and Receiver for Automatic
Telegraph. . . . . . . . . . . . . . .Jan. 18, 1875
168,243 Automatic Telegraphs . . . . . . . . .Jan. 18, 1875
168,385 Duplex Telegraphs. . . . . . . . . . .Jan. 18, 1875
168,466 Solution for Chemical Telegraphs . . .Jan. 18, 1875
168,467 Recording Point for Chemical TelegraphJan. 18, 1875
195,751 Automatic Telegraphs . . . . . . . . . Jan. 18 1875
195,752 Automatic Telegraphs . . . . . . . . .Jan. 19, 1875
171,273 Telegraph Apparatus. . . . . . . . . . Feb 11, 1875
169,972 Electric Signalling Instrument . . . . Feb 24, 1875
209,241 Quadruplex Telegraph Repeaters (reissued
September 23, 1879, numbered
8906). . . . . . . . . . . . . . . . . Feb 24, 1875
1876
180,857 Autographic Printing . . . . . . . . .March 7, 1876
198,088 Telephonic Telegraphs. . . . . . . . .April 3, 1876
198,089 Telephonic or Electro Harmonic
Telegraphs . . . . . . . . . . . . . .April 3, 1876
182,996 Acoustic Telegraphs. . . . . . . . . . .May 9, 1876
186,330 Acoustic Electric Telegraphs . . . . . .May 9, 1876
186,548 Telegraph Alarm and Signal Apparatus . .May 9, 1876
198,087 Telephonic Telegraphs. . . . . . . . . .May 9, 1876
185,507 Electro Harmonic Multiplex Telegraph .Aug. 16, 1876
200,993 Acoustic Telegraph . . . . . . . . . .Aug. 26, 1876
235,142 Acoustic Telegraph . . . . . . . . . .Aug. 26, 1876
200,032 Synchronous Movements for Electric
Telegraphs . . . . . . . . . . . . . .Oct. 30, 1876
200,994 Automatic Telegraph Perforator and
Transmitter. . . . . . . . . . . . . .Oct. 30, 1876
1877
205,370 Pneumatic Stencil Pens . . . . . . . . Feb. 3, 1877
213,554 Automatic Telegraphs . . . . . . . . . Feb. 3, 1877
196,747 Stencil Pens . . . . . . . . . . . . April 18, 1877
203,329 Perforating Pens . . . . . . . . . . April 18, 1877
474,230 Speaking Telegraph . . . . . . . . . April 18, 1877
217,781 Sextuplex Telegraph. . . . . . . . . . .May 8, 1877
230,621 Addressing Machine . . . . . . . . . . .May 8, 1877
377,374 Telegraphy . . . . . . . . . . . . . . .May 8, 1877
453,601 Sextuplex Telegraph. . . . . . . . . . May 31, 1877
452,913 Sextuplex Telegraph. . . . . . . . . . May 31, 1877
512,872 Sextuplex Telegraph. . . . . . . . . . May 31, 1877
474,231 Speaking Telegraph . . . . . . . . . . July 9, 1877
203,014 Speaking Telegraph . . . . . . . . . .July 16, 1877
208,299 Speaking Telegraph . . . . . . . . . .July 16, 1877
203,015 Speaking Telegraph . . . . . . . . . .Aug. 16, 1877
420,594 Quadruplex Telegraph . . . . . . . . .Aug. 16, 1877
492,789 Speaking Telegraph . . . . . . . . . .Aug. 31, 1877
203,013 Speaking Telegraph . . . . . . . . . . Dec. 8, 1877
203 018 Telephone or Speaking Telegraph. . . . Dec. 8, 1877
200 521 Phonograph or Speaking Machine . . . .Dec. 15, 1877
1878
203,019 Circuit for Acoustic or Telephonic
Telegraphs . . . . . . . . . . . . . .Feb. 13, 1878
201,760 Speaking Machines. . . . . . . . . . .Feb. 28, 1878
203,016 Speaking Machines. . . . . . . . . . .Feb. 28, 1878
203,017 Telephone Call Signals . . . . . . . .Feb. 28, 1878
214,636 Electric Lights. . . . . . . . . . . . Oct. 5, 1878
222,390 Carbon Telephones. . . . . . . . . . . Nov. 8, 1878
217,782 Duplex Telegraphs. . . . . . . . . . .Nov. 11, 1878
214,637 Thermal Regulator for Electric Lights.Nov. 14, 1878
210,767 Vocal Engines. . . . . . . . . . . . .Aug. 31, 1878
218,166 Magneto Electric Machines. . . . . . . Dec. 3, 1878
218,866 Electric Lighting Apparatus. . . . . . Dec. 3, 1878
219,628 Electric Lights. . . . . . . . . . . . Dec. 3, 1878
295,990 Typewriter . . . . . . . . . . . . . . Dec. 4, 1878
218,167 Electric Lights. . . . . . . . . . . .Dec. 31, 1878
1879
224,329 Electric Lighting Apparatus. . . . . .Jan. 23, 1879
227,229 Electric Lights. . . . . . . . . . . .Jan. 28, 1879
227,227 Electric Lights. . . . . . . . . . . . Feb. 6, 1879
224.665 Autographic Stencils for Printing. . March 10, 1879
227.679 Phonograph . . . . . . . . . . . . . March 19, 1879
221,957 Telephone. . . . . . . . . . . . . . March 24, 1879
227,229 Electric Lights. . . . . . . . . . . April 12, 1879
264,643 Magneto Electric Machines. . . . . . April 21, 1879
219,393 Dynamo Electric Machines . . . . . . . July 7, 1879
231,704 Electro Chemical Receiving Telephone .July 17, 1879
266,022 Telephone. . . . . . . . . . . . . . . Aug. 1, 1879
252,442 Telephone. . . . . . . . . . . . . . . Aug. 4, 1879
222,881 Magneto Electric Machines. . . . . . .Sept. 4, 1879
223,898 Electric Lamp. . . . . . . . . . . . . Nov. 1, 1879
1880
230,255 Electric Lamps . . . . . . . . . . . .Jan. 28, 1880
248,425 Apparatus for Producing High Vacuums Jan.28 1880
265,311 Electric Lamp and Holder for Same. . . Jan. 28 1880
369,280 System of Electrical Distribution. . .Jan. 28, 1880
227,226 Safety Conductor for Electric Lights .March 10,1880
228,617 Brake for Electro Magnetic Motors. . March 10, 1880
251,545 Electric Meter . . . . . . . . . . . March 10, 1880
525,888 Manufacture of Carbons for Electric
Lamps. . . . . . . . . . . . . . . . March 10, 1880
264,649 Dynamo or Magneto Electric Machines. March 11,
1880
228,329 Magnetic Ore Separator . . . . . . . .April 3, 1880
238,868 Manufacture of Carbons for Incandescent
Electric Lamps . . . . . . . . . . . April 25, 1880
237,732 Electric Light . . . . . . . . . . . .June 15, 1880
248,417 Manufacturing Carbons for Electric
Lights . . . . . . . . . . . . . . . .June 15, 1880
298,679 Treating Carbons for Electric Lights .June 15, 1880
248,430 Electro Magnetic Brake . . . . . . . . July 2, 1880
265,778 Electro Magnetic Railway Engine. . . . July 3, 1880
248,432 Magnetic Separator . . . . . . . . . .July 26, 1880
239,150 Electric Lamp. . . . . . . . . . . . .July 27, 1880
239,372 Testing Electric Light Carbons--Edison
and Batchelor. . . . . . . . . . . . .July 28, 1880
251,540 Carbon Electric Lamps. . . . . . . . .July 28, 1880
263,139 Manufacture of Carbons for Electric
Lamps. . . . . . . . . . . . . . . . .July 28, 1880
434,585 Telegraph Relay. . . . . . . . . . . .July 29, 1880
248 423 Carbonizer . . . . . . . . . . . . . .July 30, 1880
263 140 Dynamo Electric Machines . . . . . . .July 30, 1880
248,434 Governor for Electric Engines. . . . .July 31, 1880
239,147 System of Electric Lighting. . . . . .July 31, 1880
264,642 Electric Distribution and Translation
System . . . . . . . . . . . . . . . . Aug. 4, 1880
293,433 Insulation of Railroad Tracks used for
Electric Circuits. . . . . . . . . . . Aug. 6, 1880
239,373 Electric Lamp. . . . . . . . . . . . . Aug. 7, 1880
239,745 Electric Lamp. . . . . . . . . . . . . Aug. 7, 1880
263,135 Electric Lamp. . . . . . . . . . . . . Aug. 7, 1880
251,546 Electric Lamp. . . . . . . . . . . . .Aug. 10, 1880
239,153 Electric Lamp. . . . . . . . . . . . .Aug. 11, 1880
351,855 Electric Lamp. . . . . . . . . . . . .Aug. 11, 1880
248,435 Utilizing Electricity as Motive Power.Aug. 12, 1880
263,132 Electro Magnetic Roller. . . . . . . .Aug. 14, 1880
264,645 System of Conductors for the Distribution
of Electricity . . . . . . . . . . . .Sept. 1, 1880
240,678 Webermeter . . . . . . . . . . . . . Sept. 22, 1880
239,152 System of Electric Lighting. . . . . .Oct. 14, 1880
239,148 Treating Carbons for Electric Lights .Oct. 15, 1880
238,098 Magneto Signalling Apparatus--Edison
and Johnson. . . . . . . . . . . . . .Oct. 21, 1880
242,900 Manufacturing Carbons for Electric
Lamps. . . . . . . . . . . . . . . . .Oct. 21, 1880
251,556 Regulator for Magneto or Dynamo
Electric Machines. . . . . . . . . . .Oct. 21, 1880
248,426 Apparatus for Treating Carbons for
Electric Lamps . . . . . . . . . . . . Nov. 5, 1880
239,151 Forming Enlarged Ends on Carbon
Filaments. . . . . . . . . . . . . . .Nov. 19, 1880
12,631 Design Patent--Incandescent Electric
Lamp . . . . . . . . . . . . . . . . .Nov. 23, 1880
239,149 Incandescing Electric Lamp . . . . . . Dec. 3, 1880
242,896 Incandescent Electric Lamp . . . . . . Dec. 3, 1880
242,897 Incandescent Electric Lamp . . . . . . Dec. 3, 1880
248,565 Webermeter . . . . . . . . . . . . . . Dec. 3, 1880
263,878 Electric Lamp. . . . . . . . . . . . . Dec. 3, 1880
239,154 Relay for Telegraphs . . . . . . . . .Dec. 11, 1880
242,898 Dynamo Electric Machine. . . . . . . .Dec. 11, 1880
248,431 Preserving Fruit . . . . . . . . . . .Dec. 11, 1880
265,777 Treating Carbons for Electric Lamps. .Dec. 11, 1880
239,374 Regulating the Generation of Electric
Currents . . . . . . . . . . . . . . .Dec. 16, 1880
248,428 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . .Dec. 16, 1880
248,427 Apparatus for Treating Carbons for
Electric Lamps . . . . . . . . . . . .Dec. 21, 1880
248,437 Apparatus for Treating Carbons for
Electric Lamps . . . . . . . . . . . .Dec. 21, 1880
248,416 Manufacture of Carbons for Electric
Lights . . . . . . . . . . . . . . . .Dec. 30, 1880
1881
242,899 Electric Lighting. . . . . . . . . . .Jan. 19, 1881
248,418 Electric Lamp. . . . . . . . . . . . . Jan. 19 1881
248,433 Vacuum Apparatus . . . . . . . . . . . Jan. 19 1881
251,548 Incandescent Electric Lamps. . . . . .Jan. 19, 1881
406,824 Electric Meter . . . . . . . . . . . .Jan. 19, 1881
248,422 System of Electric Lighting. . . . . .Jan. 20, 1881
431,018 Dynamo or Magneto Electric Machine . . Feb. 3, 1881
242,901 Electric Motor . . . . . . . . . . . .Feb. 24, 1881
248,429 Electric Motor . . . . . . . . . . . .Feb. 24, 1881
248,421 Current Regulator for Dynamo Electric
Machine. . . . . . . . . . . . . . . .Feb. 25, 1881
251,550 Magneto or Dynamo Electric Machines. .Feb. 26, 1881
251,555 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Feb. 26, 1881
482,549 Means for Controlling Electric
Generation . . . . . . . . . . . . . .March 2, 1881
248,420 Fixture and Attachment for Electric
Lamps. . . . . . . . . . . . . . . . .March 7, 1881
251,553 Electric Chandeliers . . . . . . . . .March 7, 1881
251,554 Electric Lamp and Socket or Holder . .March 7, 1881
248,424 Fitting and Fixtures for Electric
Lamps. . . . . . . . . . . . . . . . .March 8, 1881
248,419 Electric Lamp. . . . . . . . . . . . March 30, 1881
251,542 System of Electric Light . . . . . . April 19, 1881
263,145 Making Incandescents . . . . . . . . April 19, 1881
266,447 Electric Incandescent Lamp . . . . . April 21, 1881
251,552 Underground Conductors . . . . . . . April 22, 1881
476,531 Electric Lighting System . . . . . . April 22, 1881
248,436 Depositing Cell for Plating the Connections
of Electric Lamps. . . . . . . . . . . May 17, 1881
251,539 Electric Lamp. . . . . . . . . . . . . May 17, 1881
263,136 Regulator for Dynamo or Magneto
Electric Machine . . . . . . . . . . . May 17, 1881
251,557 Webermeter . . . . . . . . . . . . . . May 19, 1881
263,134 Regulator for Magneto Electric
Machine. . . . . . . . . . . . . . . . May 19, 1881
251,541 Electro Magnetic Motor . . . . . . . . May 20, 1881
251,544 Manufacture of Electric Lamps. . . . . May 20, 1881
251,549 Electric Lamp and the Manufacture
thereof. . . . . . . . . . . . . . . . May 20, 1881
251,558 Webermeter . . . . . . . . . . . . . . May 20, 1881
341,644 Incandescent Electric Lamp . . . . . . May 20, 1881
251,551 System of Electric Lighting. . . . . . May 21, 1881
263,137 Electric Chandelier. . . . . . . . . . May 21, 1881
263,141 Straightening Carbons for Incandescent
Lamps. . . . . . . . . . . . . . . . . May 21, 1881
264,657 Incandescent Electric Lamps. . . . . . May 21, 1881
251,543 Electric Lamp. . . . . . . . . . . . . May 24, 1881
251,538 Electric Light . . . . . . . . . . . . May 27, 1881
425,760 Measurement of Electricity in Distribution
System . . . . . . . . . . . . . . . .May 3 1, 1881
251,547 Electrical Governor. . . . . . . . . . June 2, 1881
263,150 Magneto or Dynamo Electric Machines. June 3, 1881
263,131 Magnetic Ore Separator . . . . . . . . June 4, 1881
435,687 Means for Charging and Using Secondary
Batteries. . . . . . . . . . . . . . .June 21, 1881
263,143 Magneto or Dynamo Electric Machines. .June 24, 1881
251,537 Dynamo Electric Machine. . . . . . . .June 25, 1881
263,147 Vacuum Apparatus . . . . . . . . . . .July 1, 188 1
439,389 Electric Lighting System . . . . . . . July 1, 1881
263,149 Commutator for Dynamo or Magneto
Electric Machines. . . . . . . . . . .July 22, 1881
479,184 Facsimile Telegraph--Edison and Kenny.July 26, 1881
400,317 Ore Separator. . . . . . . . . . . . .Aug. 11, 1881
425,763 Commutator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Aug. 20, 1881
263,133 Dynamo or Magneto Electric Machine . .Aug. 24, 1881
263,142 Electrical Distribution System . . . .Aug. 24, 1881
264,647 Dynamo or Magneto Electric Machines. .Aug. 24, 1881
404,902 Electrical Distribution System . . . .Aug. 24, 1881
257,677 Telephone. . . . . . . . . . . . . . .Sept. 7, 1881
266,021 Telephone. . . . . . . . . . . . . . .Sept. 7, 1881
263,144 Mold for Carbonizing Incandescents . Sept. 19, 1881
265,774 Maintaining Temperatures in
Webermeters. . . . . . . . . . . . . Sept. 21, 1881
264,648 Dynamo or Magneto Electric Machines. Sept. 23, 1881
265,776 Electric Lighting System . . . . . . Sept. 27, 1881
524,136 Regulator for Dynamo Electrical
Machines . . . . . . . . . . . . . . Sept. 27, 1881
273,715 Malleableizing Iron. . . . . . . . . . Oct. 4, 1881
281,352 Webermeter . . . . . . . . . . . . . . Oct. 5, 1881
446,667 Locomotives for Electric Railways. . .Oct. 11, 1881
288,318 Regulator for Dynamo or Magneto
Electric Machines. . . . . . . . . . .Oct. 17, 1881
263,148 Dynamo or Magneto Electric Machines. Oct. 25, 1881
264,646 Dynamo or Magneto Electric Machines. Oct. 25, 1881
251,559 Electrical Drop Light. . . . . . . . .Oct. 25, 1881
266,793 Electric Distribution System . . . . .Oct. 25, 1881
358,599 Incandescent Electric Lamp . . . . . .Oct. 29, 1881
264,673 Regulator for Dynamo Electric Machine. Nov. 3, 1881
263,138 Electric Arc Light . . . . . . . . . . Nov. 7, 1881
265,775 Electric Arc Light . . . . . . . . . . .Nov. 7 1881
297,580 Electric Arc Light . . . . . . . . . . .Nov. 7 1881
263,146 Dynamo Magneto Electric Machines . . .Nov. 22, 1881
266,588 Vacuum Apparatus . . . . . . . . . . .Nov. 25, 1881
251,536 Vacuum Pump. . . . . . . . . . . . . . Dec. 5, 1881
264,650 Manufacturing Incandescent Electric
Lamps. . . . . . . . . . . . . . . . . Dec. 5, 1881
264,660 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . . Dec. 5, 1881
379,770 Incandescent Electric Lamp . . . . . . Dec. 5, 1881
293,434 Incandescent Electric Lamp . . . . . . Dec. 5, 1881
439,391 Junction Box for Electric Wires. . . . Dec. 5, 1881
454,558 Incandescent Electric Lamp . . . . . . Dec. 5, 1881
264,653 Incandescent Electric Lamp . . . . . .Dec. 13, 1881
358,600 Incandescing Electric Lamp . . . . . .Dec. 13, 1881
264,652 Incandescent Electric Lamp . . . . . .Dec. 15, 1881
278,419 Dynamo Electric Machines . . . . . . .Dec. 15, 1881
1882
265,779 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Jan. 17, 1882
264,654 Incandescent Electric Lamps. . . . . .Feb. 10, 1882
264,661 Regulator for Dynamo Electric Machines Feb. 10, 1882
264,664 Regulator for Dynamo Electric Machines Feb. 10, 1882
264,668 Regulator for Dynamo Electric Machines Feb. 10, 1882
264,669 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Feb. 10, 1882
264,671 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Feb. 10, 1882
275,613 Incandescing Electric Lamp . . . . . .Feb. 10, 1882
401,646 Incandescing Electric Lamp . . . . . .Feb. 10, 1882
264,658 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Feb. 28, 1882
264,659 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Feb. 28, 1882
265,780 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Feb. 28, 1882
265,781 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Feb. 28, 1882
278,416 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . .Feb. 28, 1882
379,771 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Feb. 28, 1882
272,034 Telephone. . . . . . . . . . . . . . March 30, 1882
274,576 Transmitting Telephone . . . . . . . March 30, 1882
274,577 Telephone. . . . . . . . . . . . . . March 30, 1882
264,662 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . . .May 1, 1882
264,663 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . . .May 1, 1882
264,665 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . . .May 1, 1882
264,666 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . . .May 1, 1882
268,205 Dynamo or Magneto Electric
Machine. . . . . . . . . . . . . . . . .May 1, 1882
273,488 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . . .May 1, 1882
273,492 Secondary Battery. . . . . . . . . . . May 19, 1882
460,122 Process of and Apparatus for
Generating Electricity . . . . . . . . May 19, 1882
466,460 Electrolytic Decomposition . . . . . .May 19,. 1882
264,672 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . . May 22, 1882
264,667 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . . May 22, 1882
265,786 Apparatus for Electrical Transmission
of Power . . . . . . . . . . . . . . . May 22, 1882
273,828 System of Underground Conductors of
Electric Distribution. . . . . . . . . May 22, 1882
379,772 System of Electrical Distribution. . . May 22, 1882
274,292 Secondary Battery. . . . . . . . . . . June 3, 1882
281,353 Dynamo or Magneto Electric Machine . . June 3, 1882
287,523 Dynamo or Magneto Electric Machine . . June 3, 1882
365,509 Filament for Incandescent Electric
Lamps. . . . . . . . . . . . . . . . . .June 3 1882
446,668 Electric Are Light . . . . . . . . . . .June 3 1882
543,985 Incandescent Conductor for Electric
Lamps. . . . . . . . . . . . . . . . . June 3, 1882
264,651 Incandescent Electric Lamps. . . . . . June 9, 1882
264,655 Incandescing Electric Lamps. . . . . . June 9, 1882
264,670 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . . June 9, 1882
273,489 Turn-Table for Electric Railway. . . . June 9, 1882
273,490 Electro Magnetic Railway System. . . . June 9, 1882
401,486 System of Electric Lighting. . . . . .June 12, 1882
476,527 System of Electric Lighting. . . . . .June 12, 1882
439,390 Electric Lighting System . . . . . . .June 19, 1882
446,666 System of Electric Lighting. . . . . .June 19, 1882
464,822 System of Distributing Electricity . .June 19, 1882
304,082 Electrical Meter . . . . . . . . . . .June 24, 1882
274,296 Manufacture of Incandescents . . . . . July 5, 1882
264,656 Incandescent Electric Lamp . . . . . . July 7, 1882
265,782 Regulator for Dynamo Electric Machines July 7, 1882
265,783 Regulator for Dynamo Electric Machines July 7, 1882
265,784 Regulator for Dynamo Electric Machines July 7, 1882
265,785 Dynamo Electric Machine. . . . . . . . July 7, 1882
273,494 Electrical Railroad. . . . . . . . . . July 7, 1882
278,418 Translating Electric Currents from High
to Low Tension . . . . . . . . . . . . July 7, 1882
293,435 Electrical Meter . . . . . . . . . . . July 7, 1882
334,853 Mold for Carbonizing . . . . . . . . . July 7, 1882
339,278 Electric Railway . . . . . . . . . . . July 7, 1882
273,714 Magnetic Electric Signalling
Apparatus. . . . . . . . . . . . . . . Aug. 5, 1882
282,287 Magnetic Electric Signalling
Apparatus. . . . . . . . . . . . . . . Aug. 5, 1882
448,778 Electric Railway . . . . . . . . . . . Aug. 5, 1882
439,392 Electric Lighting System . . . . . . .Aug. 12, 1882
271,613 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . .Aug. 25, 1882
287,518 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . .Aug. 25, 1882
406,825 Electric Meter . . . . . . . . . . . .Aug. 25, 1882
439,393 Carbonizing Chamber. . . . . . . . . .Aug. 25, 1882
273,487 Regulator for Dynamo Electric MachinesSept. 12, 1882
297,581 Incandescent Electric Lamp . . . . . Sept. 12, 1882
395,962 Manufacturing Electric Lamps . . . . Sept. 16, 1882
287,525 Regulator for Systems of Electrical
Distribution--Edison and C. L.
Clarke . . . . . . . . . . . . . . . . Oct. 4, 1882
365,465 Valve Gear . . . . . . . . . . . . . . Oct. 5, 1882
317,631 Incandescent Electric Lamp . . . . . . Oct. 7, 1882
307,029 Filament for Incandescent Lamp . . . . Oct. 9, 1882
268,206 Incandescing Electric Lamp . . . . . .Oct. 10, 1882
273,486 Incandescing Electric Lamp . . . . . .Oct. 12, 1882
274,293 Electric Lamp. . . . . . . . . . . . .Oct. 14, 1882
275,612 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . .Oct. 14, 1882
430,932 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . .Oct. 14, 1882
271,616 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Oct. 16, 1882
543,986 Process for Treating Products Derived
from Vegetable Fibres. . . . . . . . .Oct. 17, 1882
543,987 Filament for Incandescent Lamps. . . .Oct. 17, 1882
271,614 Shafting . . . . . . . . . . . . . . .Oct. 19, 1882
271,615 Governor for Dynamo Electric
Machines . . . . . . . . . . . . . . .Oct. 19, 1882
273,491 Regulator for Driving Engines of
Electrical Generators. . . . . . . . .Oct. 19, 1882
273,493 Valve Gear for Electrical Generator
Engines. . . . . . . . . . . . . . . .Oct. 19, 1882
411,016 Manufacturing Carbon Filaments . . . .Oct. 19, 1882
492,150 Coating Conductors for Incandescent
Lamps. . . . . . . . . . . . . . . . .Oct. 19, 1882
273,485 Incandescent Electric Lamps. . . . . .Oct. 26, 1882
317,632 Incandescent Electric Lamps. . . . . .Oct. 26, 1882
317,633 Incandescent Electric Lamps. . . . . .Oct. 26, 1882
287,520 Incandescing Conductor for Electric
Lamps. . . . . . . . . . . . . . . . . Nov. 3, 1882
353,783 Incandescent Electric Lamp . . . . . . Nov. 3, 1882
430,933 Filament for Incandescent Lamps. . . . Nov. 3, 1882
274,294 Incandescent Electric Lamp . . . . . .Nov. 13, 1882
281,350 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Nov. 13, 1882
274,295 Incandescent Electric Lamp . . . . . .Nov. 14, 1882
276,233 Electrical Generator and Motor . . . .Nov. 14, 1882
274,290 System of Electrical Distribution. . .Nov. 20, 1882
274,291 Mold for Carbonizer. . . . . . . . . .Nov. 28, 1882
278,413 Regulator for Dynamo Electric MachinesNov. 28, 1882
278,414 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Nov. 28, 1882
287,519 Manufacturing Incandescing Electric
Lamps. . . . . . . . . . . . . . . . .Nov. 28, 1882
287,524 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Nov. 28, 1882
438,298 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . .Nov. 28, 1882
276,232 Operating and Regulating Electrical
Generators . . . . . . . . . . . . . .Dec. 20, 1882
1883
278,415 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . .Jan. 13, 1883
278,417 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . .Jan. 13, 1883
281,349 Regulator for Dynamo Electric
Machines . . . . . . . . . . . . . . .Jan. 13, 1883
283,985 System of Electrical Distribution. . . Jan. 13 1883
283,986 System o' Electrical Distribution. . . Jan. 13 1883
459,835 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . .Jan. 13, 1883
13,940 Design Patent--Incandescing Electric
Lamp . . . . . . . . . . . . . . . . . Feb. 13 1883
280,727 System of Electrical Distribution. . . Feb. 13 1883
395,123 Circuit Controller for Dynamo Machine.Feb. 13, 1883
287,521 Dynamo or Magneto Electric Machine . .Feb. 17, 1883
287,522 Molds for Carbonizing. . . . . . . . .Feb. 17, 1883
438,299 Manufacture of Carbon Filaments. . . .Feb. 17, 1883
446,669 Manufacture of Filaments for Incandescent
Electric Lamps . . . . . . . . . . . .Feb. 17, 1883
476,528 Incandescent Electric Lamp . . . . . .Feb. 17, 1883
281,351 Electrical Generator . . . . . . . . .March 5, 1883
283,984 System of Electrical Distribution. . .March 5, 1883
287,517 System of Electrical Distribution. . .March 14,1883
283,983 System of Electrical Distribution. . .April 5, 1883
354,310 Manufacture of Carbon Conductors . . .April 6, 1883
370,123 Electric Meter . . . . . . . . . . . .April 6, 1883
411,017 Carbonizing Flask. . . . . . . . . . .April 6, 1883
370,124 Manufacture of Filament for Incandescing
Electric Lamp. . . . . . . . . . . . April 12, 1883
287,516 System of Electrical Distribution. . . .May 8, 1883
341,839 Incandescent Electric Lamp . . . . . . .May 8, 1883
398,774 Incandescent Electric Lamp . . . . . . .May 8, 1883
370,125 Electrical Transmission of Power . . . June 1, 1883
370,126 Electrical Transmission of Power . . . June 1, 1883
370,127 Electrical Transmission of Power . . . June 1, 1883
370,128 Electrical Transmission of Power . . . June 1, 1883
370,129 Electrical Transmission of Power . . . June 1, 1883
370,130 Electrical Transmission of Power . . . June 1, 1883
370,131 Electrical Transmission of Power . . . June 1, 1883
438,300 Gauge for Testing Fibres for
Incandescent Lamp Carbons. . . . . . . June 1, 1883
287,511 Electric Regulator . . . . . . . . . .June 25, 1883
287,512 Dynamo Electric Machine. . . . . . . .June 25, 1883
287,513 Dynamo Electric Machine. . . . . . . .June 25, 1883
287,514 Dynamo Electric Machine. . . . . . . .June 25, 1883
287,515 System of Electrical Distribution. . .June 25, 1883
297,582 Dynamo Electric Machine. . . . . . . .June 25, 1883
328,572 Commutator for Dynamo Electric MachinesJune 25, 1883
430,934 Electric Lighting System . . . . . . .June 25, 1883
438,301 System of Electric Lighting. . . . . .June 25, 1883
297,583 Dynamo Electric Machines . . . . . . .July 27, 1883
304,083 Dynamo Electric Machines . . . . . . .July 27; 1883
304,084 Device for Protecting Electric Light
Systems from Lightning . . . . . . . .July 27, 1883
438,302 Commutator for Dynamo Electric
Machine. . . . . . . . . . . . . . . .July 27, 1883
476,529 System of Electrical Distribution. . .July 27, 1883
297,584 Dynamo Electric Machine. . . . . . . . Aug. 8, 1883
307,030 Electrical Meter . . . . . . . . . . . Aug. 8, 1883
297,585 Incandescing Conductor for Electric
Lamps. . . . . . . . . . . . . . . . Sept. 14, 1883
297,586 Electrical Conductor . . . . . . . . Sept. 14, 1883
435,688 Process and Apparatus for Generating
Electricity. . . . . . . . . . . . . Sept. 14, 1883
470,922 Manufacture of Filaments for
Incandescent Lamps . . . . . . . . . Sept. 14, 1883
490,953 Generating Electricity . . . . . . . . Oct. 9, 1883
293,432 Electrical Generator or Motor. . . . .Oct. 17, 1883
307,031 Electrical Indicator . . . . . . . . . Nov. 2, 1883
337,254 Telephone--Edison and Bergmann . . . .Nov. 10, 1883
297,587 Dynamo Electric Machine. . . . . . . .Nov. 16, 1883
298,954 Dynamo Electric Machine. . . . . . . .Nov. 15, 1883
298,955 Dynamo Electric Machine. . . . . . . .Nov. 15, 1883
304,085 System of Electrical Distribution. . .Nov. 15, 1883
509,517 System of Electrical Distribution. . .Nov. 15, 1883
425,761 Incandescent Lamp. . . . . . . . . . .Nov. 20, 1883
304,086 Incandescent Electric Lamp . . . . . .Dec. 15, 1883
1884
298,956 Operating Dynamo Electric Machine. . . Jan. 5, 1884
304,087 Electrical Conductor . . . . . . . . .Jan. 12, 1884
395,963 Incandescent Lamp Filament . . . . . .Jan. 22, 1884
526,147 Plating One Material with Another. . .Jan. 22, 1884
339,279 System of Electrical Distribution. . . Feb. 8, 1884
314,115 Chemical Stock Quotation Telegraph--
Edison and Kenny . . . . . . . . . . . Feb. 9, 1884
436,968 Method and Apparatus for Drawing
Wire . . . . . . . . . . . . . . . . . June 2, 1884
436,969 Apparatus for Drawing Wire . . . . . . June 2, 1884
438,303 Arc Lamp . . . . . . . . . . . . . . . June 2, 1884
343,017 System of Electrical Distribution. . .June 27, 1884
391,595 System of Electric Lighting. . . . . .July 16, 1884
328,573 System of Electric Lighting. . . . . Sept. 12, 1884
328,574 System of Electric Lighting. . . . . Sept. 12, 1884
328,575 System of Electric Lighting. . . . . Sept. 12, 1884
391,596 Incandescent Electric Lamp . . . . . Sept. 24, 1884
438,304 Electric Signalling Apparatus. . . . Sept. 24, 1884
422,577 Apparatus for Speaking Telephones--
Edison and Gilliland . . . . . . . . .Oct. 21, 1884
329,030 Telephone. . . . . . . . . . . . . . . Dec. 3, 1884
422,578 Telephone Repeater . . . . . . . . . . Dec. 9, 1884
422,579 Telephone Repeater . . . . . . . . . . Dec. 9, 1884
340,707 Telephonic Repeater. . . . . . . . . . Dec. 9, 1884
340,708 Electrical Signalling Apparatus. . . .Dec. 19, 1884
347,097 Electrical Signalling Apparatus. . . .Dec. 19, 1884
478,743 Telephone Repeater . . . . . . . . . .Dec. 31, 1884
1885
340,709 Telephone Circuit--Edison and
Gilliland. . . . . . . . . . . . . . . Jan. 2, 1885
378,044 Telephone Transmitter. . . . . . . . . Jan. 9, 1885
348,114 Electrode for Telephone Transmitters .Jan. 12, 1885
438,305 Fuse Block . . . . . . . . . . . . . .Jan. 14, 1885
350,234 System of Railway Signalling--Edison
and Gilliland. . . . . . . . . . . . .March 27,1885
486,634 System of Railway Signalling--Edison
and Gilliland. . . . . . . . . . . . .March 27,1885
333,289 Telegraphy . . . . . . . . . . . . . April 27, 1885
333,290 Duplex Telegraphy. . . . . . . . . . April 30, 1885
333,291 Way Station Quadruplex Telegraph . . . .May 6, 1885
465,971 Means for Transmitting Signals ElectricallyMay 14, 1885
422 072 Telegraphy . . . . . . . . . . . . . . Oct. 7, 1885
437 422 Telegraphy . . . . . . . . . . . . . . Oct. 7, 1885
422,073 Telegraphy . . . . . . . . . . . . . Nov. I 2, 1885
422,074 Telegraphy . . . . . . . . . . . . . .Nov. 24, 1885
435,689 Telegraphy . . . . . . . . . . . . . .Nov. 30, 1885
438,306 Telephone - Edison and Gilliland . . .Dec. 22, 1885
350,235 Railway Telegraphy--Edison and
Gilliland. . . . . . . . . . . . . . .Dec. 28, 1885
1886
406,567 Telephone. . . . . . . . . . . . . . .Jan. 28, 1886
474,232 Speaking Telegraph . . . . . . . . . .Feb. 17, 1886
370 132 Telegraphy . . . . . . . . . . . . . . May 11, 1886
411,018 Manufacture of Incandescent Lamps. . .July 15, 1886
438,307 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . July I 5, 1886
448,779 Telegraph. . . . . . . . . . . . . . .July IS, 1886
411,019 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . .July 20, 1886
406,130 Manufacture of Incandescent Electric
Lamps. . . . . . . . . . . . . . . . . Aug. 6, 1886
351,856 Incandescent Electric Lamp . . . . . Sept. 30, 1886
454,262 Incandescent Lamp Filaments. . . . . .Oct. 26, 1886
466,400 Cut-Out for Incandescent Lamps--Edison
and J. F. Ott. . . . . . . . . . . . .Oct. 26, 1886
484,184 Manufacture of Carbon Filaments. . . .Oct. 26, 1886
490,954 Manufacture of Carbon Filaments for
Electric Lamps . . . . . . . . . . . . Nov. 2, 1886
438,308 System of Electrical Distribution. . . Nov. 9, 1886
524,378 System of Electrical Distribution. . . Nov. 9, 1886
365,978 System of Electrical Distribution. . .Nov. 22, 1886
369 439 System of Electrical Distribution. . .Nov. 22, 1886
384 830 Railway Signalling--Edison and GillilandNov. 24, 1886
379,944 Commutator for Dynamo Electric MachinesNov. 26, 1886
411,020 Manufacture of Carbon Filaments. . . .Nov. 26, 1886
485,616 Manufacture of Carbon Filaments. . . . .Dec 6, 1886
485,615 Manufacture of Carbon Filaments. . . . .Dec 6, 1886
525,007 Manufacture of Carbon Filaments. . . . Dec. 6, 1886
369,441 System of Electrical Distribution. . .Dec. 10, 1886
369,442 System of Electrical Distribution. . .Dec. 16, 1886
369,443 System of Electrical Distribution. . .Dec. 16, 1886
484,185 Manufacture of Carbon Filaments. . . .Dec. 20, 1886
534,207 Manufacture of Carbon Filaments. . . .Dec. 20, 1886
373,584 Dynamo Electric Machine. . . . . . . .Dec. 21, 1886
1887
468,949 Converter System for Electric
Railways . . . . . . . . . . . . . . . Feb. 7, 1887
380,100 Pyromagnetic Motor . . . . . . . . . . May 24, 1887
476,983 Pyromagnetic Generator . . . . . . . . .May 24 1887
476,530 Incandescent Electric Lamp . . . . . . June 1, 1887
377,518 Magnetic Separator . . . . . . . . . .June 30, 1887
470,923 Railway Signalling . . . . . . . . . . Aug. 9, 1887
545,405 System of Electrical Distribution. . .Aug. 26, 1887
380,101 System of Electrical Distribution. . .Sept. 13 1887
380,102 System of Electrical Distribution. . .Sept. 14 1887
470,924 Electric Conductor . . . . . . . . . Sept. 26, 1887
563,462 Method of and Apparatus for Drawing
Wire . . . . . . . . . . . . . . . . .Oct. 17, 1887
385,173 System of Electrical Distribution. . . Nov. 5, 1887
506,215 Making Plate Glass . . . . . . . . . . Nov. 9, 1887
382,414 Burnishing Attachments for PhonographsNov. 22, 1887
386,974 Phonograph . . . . . . . . . . . . . .Nov. 22, 1887
430,570 Phonogram Blank. . . . . . . . . . . .Nov. 22, 1887
382,416 Feed and Return Mechanism for PhonographsNov. 29, 1887
382,415 System of Electrical Distribution. . . Dec. 4, 1887
382,462 Phonogram Blanks . . . . . . . . . . . Dec. 5, 1887
1888
484,582 Duplicating Phonograms . . . . . . . .Jan. 17, 1888
434,586 Electric Generator . . . . . . . . . .Jan. 21, 1888
434,587 Thermo Electric Battery. . . . . . . .Jan. 21, 1888
382,417 Making Phonogram Blanks. . . . . . . .Jan. 30, 1888
389,369 Incandescing Electric Lamp . . . . . . Feb. 2, 1888
382,418 Phonogram Blank. . . . . . . . . . . .Feb. 20, 1888
390,462 Making Carbon Filaments. . . . . . . .Feb. 20, 1888
394,105 Phonograph Recorder. . . . . . . . . .Feb. 20, 1888
394,106 Phonograph Reproducer. . . . . . . . .Feb. 20, 1888
382,419 Duplicating Phonograms . . . . . . . .March 3, 1888
425,762 Cut-Out for Incandescent Lamps . . . .March 3, 1888
396,356 Magnetic Separator . . . . . . . . . .March 19,1888
393,462 Making Phonogram Blanks. . . . . . . April 28, 1888
393,463 Machine for Making Phonogram Blanks. April 28, 1888
393,464 Machine for Making Phonogram Blanks. April 28, 1888
534,208 Induction Converter. . . . . . . . . . .May 7, 1888
476,991 Method of and Apparatus for Separating
Ores . . . . . . . . . . . . . . . . . .May 9, 1888
400,646 Phonograph Recorder and Reproducer . . May 22, 1888
488,190 Phonograph Reproducer. . . . . . . . . May 22, 1888
488,189 Phonograph . . . . . . . . . . . . . . May 26, 1888
470,925 Manufacture of Filaments for Incandescent
Electric Lamps . . . . . . . . . . . .June 21, 1888
393,465 Preparing Phonograph Recording SurfacesJune 30, 1888
400,647 Phonograph . . . . . . . . . . . . . .June 30, 1888
448,780 Device for Turning Off Phonogram BlanksJune 30, 1888
393,466 Phonograph Recorder. . . . . . . . . .July 14, 1888
393,966 Recording and Reproducing Sounds . . .July 14, 1888
393,967 Recording and Reproducing Sounds . . .July 14, 1888
430,274 Phonogram Blank. . . . . . . . . . . .July 14, 1888
437,423 Phonograph . . . . . . . . . . . . . .July 14, 1888
450,740 Phonograph Recorder. . . . . . . . . .July 14, 1888
485,617 Incandescent Lamp Filament . . . . . .July 14, 1888
448,781 Turning-Off Device for Phonographs . .July 16, 1888
400,648 Phonogram Blank. . . . . . . . . . . .July 27, 1888
499,879 Phonograph . . . . . . . . . . . . . .July 27, 1888
397,705 Winding Field Magnets. . . . . . . . .Aug. 31, 1888
435,690 Making Armatures for Dynamo Electric
Machines . . . . . . . . . . . . . . .Aug. 31, 1888
430,275 Magnetic Separator . . . . . . . . . Sept. 12, 1888
474,591 Extracting Gold from Sulphide Ores . Sept. 12, 1888
397,280 Phonograph Recorder and Reproducer . Sept. 19, 1888
397,706 Phonograph . . . . . . . . . . . . . Sept. 29, 1888
400,649 Making Phonogram Blanks. . . . . . . Sept. 29, 1888
400,650 Making Phonogram Blanks. . . . . . . .Oct. 15, 1888
406,568 Phonograph . . . . . . . . . . . . . .Oct. 15, 1888
437,424 Phonograph . . . . . . . . . . . . . .Oct. 15, 1888
393,968 Phonograph Recorder. . . . . . . . . .Oct. 31, 1888
1889
406,569 Phonogram Blank. . . . . . . . . . . .Jan. 10, 1889
488,191 Phonogram Blank. . . . . . . . . . . .Jan. 10, 1889
430,276 Phonograph . . . . . . . . . . . . . .Jan. 12, 1889
406,570 Phonograph . . . . . . . . . . . . . . Feb. 1, 1889
406,571 Treating Phonogram Blanks. . . . . . . Feb. 1, 1889
406,572 Automatic Determining Device for
Phonographs. . . . . . . . . . . . . . Feb. 1, 1889
406,573 Automatic Determining Device for
Phonographs. . . . . . . . . . . . . . Feb. 1, 1889
406,574 Automatic Determining Device for
Phonographs. . . . . . . . . . . . . . Feb. 1, 1889
406,575 Automatic Determining Device for
Phonographs. . . . . . . . . . . . . . Feb. 1, 1889
406,576 Phonogram Blank. . . . . . . . . . . . Feb. 1, 1889
430,277 Automatic Determining Device for
Phonographs. . . . . . . . . . . . . . Feb. 1, 1889
437,425 Phonograph Recorder. . . . . . . . . . Feb. 1, 1889
414,759 Phonogram Blanks . . . . . . . . . . March 22, 1889
414,760 Phonograph . . . . . . . . . . . . . March 22, 1889
462,540 Incandescent Electric Lamps. . . . . March 22, 1889
430,278 Phonograph . . . . . . . . . . . . . .April 8, 1889
438,309 Insulating Electrical Conductors . . April 25, 1889
423,039 Phonograph Doll or Other Toys. . . . .June 15, 1889
426,527 Automatic Determining Device for
Phonographs. . . . . . . . . . . . . .June 15, 1889
430,279 Voltaic Battery. . . . . . . . . . . .June 15, 1889
506,216 Apparatus for Making Glass . . . . . .June 29, 1889
414,761 Phonogram Blanks . . . . . . . . . . .July 16, 1889
430,280 Magnetic Separator . . . . . . . . . .July 20, 1889
437,426 Phonograph . . . . . . . . . . . . . .July 20, 1889
465,972 Phonograph . . . . . . . . . . . . . .Nov. 14, 1889
443,507 Phonograph . . . . . . . . . . . . . . Dec. 11 1889
513,095 Phonograph . . . . . . . . . . . . . . Dec. 11 1889
1890
434,588 Magnetic Ore Separator--Edison and
W. K. L. Dickson . . . . . . . . . . .Jan. 16, 1890
437,427 Making Phonogram Blanks. . . . . . . . Feb. 8, 1890
465,250 Extracting Copper Pyrites. . . . . . . Feb. 8, 1890
434,589 Propelling Mechanism for Electric VehiclesFeb. 14, 1890
438,310 Lamp Base. . . . . . . . . . . . . . April 25, 1890
437,428 Propelling Device for Electric Cars. April 29, 1890
437,429 Phonogram Blank. . . . . . . . . . . April 29, 1890
454,941 Phonograph Recorder and Reproducer . . .May 6, 1890
436,127 Electric Motor . . . . . . . . . . . . May 17, 1890
484,583 Phonograph Cutting Tool. . . . . . . . May 24, 1890
484,584 Phonograph Reproducer. . . . . . . . . May 24, 1890
436,970 Apparatus for Transmitting Power . . . June 2, 1890
453,741 Phonograph . . . . . . . . . . . . . . July 5, 1890
454,942 Phonograph . . . . . . . . . . . . . . July 5, 1890
456,301 Phonograph Doll. . . . . . . . . . . . July 5, 1890
484,585 Phonograph . . . . . . . . . . . . . . July 5, 1890
456,302 Phonograph . . . . . . . . . . . . . . Aug. 4, 1890
476,984 Expansible Pulley. . . . . . . . . . . Aug. 9, 1890
493,858 Transmission of Power. . . . . . . . . Aug. 9, 1890
457,343 Magnetic Belting . . . . . . . . . . .Sept. 6, 1890
444,530 Leading-in Wires for Incandescent Electric
Lamps (reissued October 10, 1905,
No. 12,393). . . . . . . . . . . . . Sept. 12, 1890
534 209 Incandescent Electric Lamp . . . . . Sept. 13, 1890
476 985 Trolley for Electric Railways. . . . .Oct. 27, 1890
500,280 Phonograph . . . . . . . . . . . . . .Oct. 27, 1890
541,923 Phonograph . . . . . . . . . . . . . .Oct. 27, 1890
457,344 Smoothing Tool for Phonogram
Blanks . . . . . . . . . . . . . . . .Nov. 17, 1890
460,123 Phonogram Blank Carrier. . . . . . . .Nov. 17, 1890
500,281 Phonograph . . . . . . . . . . . . . .Nov. 17, 1890
541,924 Phonograph . . . . . . . . . . . . . .Nov. 17, 1890
500,282 Phonograph . . . . . . . . . . . . . . Dec. 1, 1890
575,151 Phonograph . . . . . . . . . . . . . . Dec. 1, 1890
605,667 Phonograph . . . . . . . . . . . . . . Dec. 1, 1890
610,706 Phonograph . . . . . . . . . . . . . . Dec. 1, 1890
622,843 Phonograph . . . . . . . . . . . . . . Dec. 1, 1890
609,268 Phonograph . . . . . . . . . . . . . . Dec. 6, 1890
493,425 Electric Locomotive. . . . . . . . . .Dec. 20, 1890
1891
476,992 Incandescent Electric Lamp . . . . . .Jan. 20, 1891
470,926 Dynamo Electric Machine or Motor . . . Feb. 4, 1891
496,191 Phonograph . . . . . . . . . . . . . . Feb. 4, 1891
476,986 Means for Propelling Electric Cars . .Feb. 24, 1891
476,987 Electric Locomotive. . . . . . . . . .Feb. 24, 1891
465,973 Armatures for Dynamos or Motors. . . .March 4, 1891
470,927 Driving Mechanism for Cars . . . . . .March 4, 1891
465,970 Armature Connection for Motors or
Generators . . . . . . . . . . . . . March 20, 1891
468,950 Commutator Brush for Electric Motors
and Dynamos. . . . . . . . . . . . . March 20, 1891
475,491 Electric Locomotive. . . . . . . . . . June 3, 1891
475,492 Electric Locomotive. . . . . . . . . . June 3, 1891
475,493 Electric Locomotive. . . . . . . . . . June 3, 1891
475,494 Electric Railway . . . . . . . . . . . June 3, 1891
463,251 Bricking Fine Ores . . . . . . . . . .July 31, 1891
470,928 Alternating Current Generator. . . . .July 31, 1891
476,988 Lightning Arrester . . . . . . . . . .July 31, 1891
476,989 Conductor for Electric Railways. . . .July 31, 1891
476,990 Electric Meter . . . . . . . . . . . .July 31, 1891
476,993 Electric Arc . . . . . . . . . . . . .July 31, 1891
484,183 Electrical Depositing Meter. . . . . .July 31, 1891
485,840 Bricking Fine Iron Ores. . . . . . . .July 31, 1891
493,426 Apparatus for Exhibiting Photographs
of Moving Objects. . . . . . . . . . .July 31, 1891
509,518 Electric Railway . . . . . . . . . . .July 31, 1891
589,168 Kinetographic Camera (reissued September
30, 1902, numbered 12,037
and 12,038, and January 12, 1904,
numbered 12,192) . . . . . . . . . . .July 31, 1891
470,929 Magnetic Separator . . . . . . . . . .Aug. 28, 1891
471,268 Ore Conveyor and Method of Arranging
Ore Thereon. . . . . . . . . . . . . .Aug. 28, 1891
472,288 Dust-Proof Bearings for Shafts . . . .Aug. 28, 1891
472,752 Dust-Proof Journal Bearings. . . . . .Aug. 28, 1891
472,753 Ore-Screening Apparatus. . . . . . . .Aug. 28, 1891
474,592 Ore-Conveying Apparatus. . . . . . . .Aug. 28, 1891
474,593 Dust-Proof Swivel Shaft Bearing. . . .Aug. 28, 1891
498,385 Rollers for Ore-Crushing or Other
Material . . . . . . . . . . . . . . .Aug. 28, 1891
470,930 Dynamo Electric Machine. . . . . . . . .Oct 8, 1891
476,532 Ore-Screening Apparatus. . . . . . . . .Oct 8, 1891
491,992 Cut-Out for Incandescent Electric LampsNov. 10, 1891
1892
491,993 Stop Device. . . . . . . . . . . . . . April 5 1892
564,423 Separating Ores. . . . . . . . . . . .June 2;, 1892
485,842 Magnetic Ore Separation. . . . . . . . July 9, 1892
485,841 Mechanically Separating Ores . . . . . July 9, 1892
513,096 Method of and Apparatus for Mixing
Materials. . . . . . . . . . . . . . .Aug. 24, 1892
1893
509,428 Composition Brick and Making Same. . March 15, 1893
513,097 Phonograph . . . . . . . . . . . . . . May 22, 1893
567,187 Crushing Rolls . . . . . . . . . . . .Dec. 13, 1893
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