Full Text Archive logoFull Text Archive — Free Classic E-books

Edison, His Life and Inventions by Frank Lewis Dyer and Thomas Commerford Martin

Part 5 out of 17

Adobe PDF icon
Download this document as a .pdf
File size: 1.8 MB
What's this? light bulb idea Many people prefer to read off-line or to print out text and read from the real printed page. Others want to carry documents around with them on their mobile phones and read while they are on the move. We have created .pdf files of all out documents to accommodate all these groups of people. We recommend that you download .pdfs onto your mobile phone when it is connected to a WiFi connection for reading off-line.

joint between the metal base and the glass globe, and
also provided their lamps with several short carbon
pencils, which were automatically brought into circuit
successively as the pencils were consumed. In
1876 or 1877, Bouliguine proposed the employment
of a long carbon pencil, a short section only of
which was in circuit at any one time and formed the
burner, the lamp being provided with a mechanism
for automatically pushing other sections of the pencil
into position between the contacts to renew the
burner. Sawyer and Man proposed, in 1878, to make
the bottom plate of glass instead of metal, and
provided ingenious arrangements for charging the
lamp chamber with an atmosphere of pure nitrogen
gas which does not support combustion.

These lamps and many others of similar character,
ingenious as they were, failed to become of any commercial
value, due, among other things, to the brief
life of the carbon burner. Even under the best conditions
it was found that the carbon members were
subject to a rapid disintegration or evaporation,
which experimenters assumed was due to the disrupting
action of the electric current; and hence the
conclusion that carbon contained in itself the elements
of its own destruction, and was not a suitable
material for the burner of an incandescent lamp.
On the other hand, platinum, although found to be
the best of all materials for the purpose, aside from
its great expense, and not combining with oxygen at
high temperatures as does carbon, required to be
brought so near the melting-point in order to give
light, that a very slight increase in the temperature
resulted in its destruction. It was assumed that the
difficulty lay in the material of the burner itself, and
not in its environment.

It was not realized up to such a comparatively
recent date as 1879 that the solution of the great
problem of subdivision of the electric current would
not, however, be found merely in the production of
a durable incandescent electric lamp--even if any of
the lamps above referred to had fulfilled that requirement.
The other principal features necessary
to subdivide the electric current successfully were:
the burning of an indefinite number of lights on the
same circuit; each light to give a useful and economical
degree of illumination; and each light to be independent
of all the others in regard to its operation
and extinguishment.

The opinions of scientific men of the period on the
subject are well represented by the two following
extracts--the first, from a lecture at the Royal
United Service Institution, about February, 1879,
by Mr. (Sir) W. H. Preece, one of the most eminent
electricians in England, who, after discussing the
question mathematically, said: "Hence the sub-division
of the light is an absolute ignis fatuus." The
other extract is from a book written by Paget Higgs,
LL.D., D.Sc., published in London in 1879, in which
he says: "Much nonsense has been talked in relation
to this subject. Some inventors have claimed the
power to `indefinitely divide' the electric current, not
knowing or forgetting that such a statement is incompatible
with the well-proven law of conservation
of energy."

"Some inventors," in the last sentence just quoted,
probably--indeed, we think undoubtedly--refers to
Edison, whose earlier work in electric lighting (1878)
had been announced in this country and abroad, and
who had then stated boldly his conviction of the
practicability of the subdivision of the electrical current.
The above extracts are good illustrations,
however, of scientific opinions up to the end of 1879,
when Mr. Edison's epoch-making invention rendered
them entirely untenable. The eminent scientist,
John Tyndall, while not sharing these precise views,
at least as late as January 17, 1879, delivered a
lecture before the Royal Institution on "The
Electric Light," when, after pointing out the
development of the art up to Edison's work, and
showing the apparent hopelessness of the problem, he
said: "Knowing something of the intricacy of the
practical problem, I should certainly prefer seeing it
in Edison's hands to having it in mine."

The reader may have deemed this sketch of the
state of the art to be a considerable digression; but
it is certainly due to the subject to present the facts
in such a manner as to show that this great invention
was neither the result of improving some process or
device that was known or existing at the time, nor
due to any unforeseen lucky chance, nor the accidental
result of other experiments. On the contrary, it was
the legitimate outcome of a series of exhaustive
experiments founded upon logical and original reasoning
in a mind that had the courage and hardihood to
set at naught the confirmed opinions of the world,
voiced by those generally acknowledged to be the
best exponents of the art--experiments carried on
amid a storm of jeers and derision, almost as
contemptuous as if the search were for the discovery of
perpetual motion. In this we see the man foreshadowed
by the boy who, when he obtained his books
on chemistry or physics, did not accept any statement
of fact or experiment therein, but worked out every
one of them himself to ascertain whether or not they
were true.

Although this brings the reader up to the year
1879, one must turn back two years and accompany
Edison in his first attack on the electric-light problem.
In 1877 he sold his telephone invention (the carbon
transmitter) to the Western Union Telegraph Company,
which had previously come into possession also
of his quadruplex inventions, as already related. He
was still busily engaged on the telephone, on acoustic
electrical transmission, sextuplex telegraphs, duplex
telegraphs, miscellaneous carbon articles, and other
inventions of a minor nature. During the whole of
the previous year and until late in the summer of
1877, he had been working with characteristic energy
and enthusiasm on the telephone; and, in developing
this invention to a successful issue, had preferred the
use of carbon and had employed it in numerous
forms, especially in the form of carbonized paper.

Eighteen hundred and seventy-seven in Edison's
laboratory was a veritable carbon year, for it was
carbon in some shape or form for interpolation in
electric circuits of various kinds that occupied the
thoughts of the whole force from morning to night.
It is not surprising, therefore, that in September of
that year, when Edison turned his thoughts actively
toward electric lighting by incandescence, his early
experiments should be in the line of carbon as an
illuminant. His originality of method was displayed
at the very outset, for one of the first experiments
was the bringing to incandescence of a strip of carbon
in the open air to ascertain merely how much current
was required. This conductor was a strip of carbonized
paper about an inch long, one-sixteenth of an
inch broad, and six or seven one-thousandths of an
inch thick, the ends of which were secured to clamps
that formed the poles of a battery. The carbon
was lighted up to incandescence, and, of course,
oxidized and disintegrated immediately. Within a
few days this was followed by experiments with the
same kind of carbon, but in vacuo by means of a
hand-worked air-pump. This time the carbon strip
burned at incandescence for about eight minutes.
Various expedients to prevent oxidization were tried,
such, for instance, as coating the carbon with powdered
glass, which in melting would protect the
carbon from the atmosphere, but without successful

Edison was inclined to concur in the prevailing
opinion as to the easy destructibility of carbon, but,
without actually settling the point in his mind, he
laid aside temporarily this line of experiment and
entered a new field. He had made previously some
trials of platinum wire as an incandescent burner
for a lamp, but left it for a time in favor of carbon.
He now turned to the use of almost infusible metals--
such as boron, ruthenium, chromium, etc.--as separators
or tiny bridges between two carbon points,
the current acting so as to bring these separators to
a high degree of incandescence, at which point they
would emit a brilliant light. He also placed some of
these refractory metals directly in the circuit, bringing
them to incandescence, and used silicon in powdered
form in glass tubes placed in the electric circuit. His
notes include the use of powdered silicon mixed with
lime or other very infusible non-conductors or semi-
conductors. Edison's conclusions on these substances
were that, while in some respects they were
within the bounds of possibility for the subdivision
of the electric current, they did not reach the ideal
that he had in mind for commercial results.

Edison's systematized attacks on the problem were
two in number, the first of which we have just related,
which began in September, 1877, and continued
until about January, 1878. Contemporaneously,
he and his force of men were very busily engaged
day and night on other important enterprises
and inventions. Among the latter, the phonograph
may be specially mentioned, as it was invented in
the late fall of 1877. From that time until July,
1878, his time and attention day and night were almost
completely absorbed by the excitement caused
by the invention and exhibition of the machine. In
July, feeling entitled to a brief vacation after several
years of continuous labor, Edison went with the
expedition to Wyoming to observe an eclipse of the
sun, and incidentally to test his tasimeter, a delicate
instrument devised by him for measuring heat transmitted
through immense distances of space. His trip
has been already described. He was absent about
two months. Coming home rested and refreshed,
Mr. Edison says: "After my return from the trip to
observe the eclipse of the sun, I went with Professor
Barker, Professor of Physics in the University of
Pennsylvania, and Doctor Chandler, Professor of
Chemistry in Columbia College, to see Mr. Wallace,
a large manufacturer of brass in Ansonia, Connecticut.
Wallace at this time was experimenting on
series arc lighting. Just at that time I wanted to
take up something new, and Professor Barker suggested
that I go to work and see if I could subdivide
the electric light so it could be got in small units like
gas. This was not a new suggestion, because I had
made a number of experiments on electric lighting a
year before this. They had been laid aside for the
phonograph. I determined to take up the search
again and continue it. On my return home I started
my usual course of collecting every kind of data
about gas; bought all the transactions of the gas-
engineering societies, etc., all the back volumes of
gas journals, etc. Having obtained all the data, and
investigated gas-jet distribution in New York by
actual observations, I made up my mind that the
problem of the subdivision of the electric current
could be solved and made commercial." About the
end of August, 1878, he began his second organized
attack on the subdivision of the current, which was
steadily maintained until he achieved signal victory
a year and two months later.

The date of this interesting visit to Ansonia is
fixed by an inscription made by Edison on a glass
goblet which he used. The legend in diamond
scratches runs: "Thomas A. Edison, September 8,
1878, made under the electric light." Other members
of the party left similar memorials, which under the
circumstances have come to be greatly prized. A
number of experiments were witnessed in arc lighting,
and Edison secured a small Wallace-Farmer dynamo
for his own work, as well as a set of Wallace arc
lamps for lighting the Menlo Park laboratory. Before
leaving Ansonia, Edison remarked, significantly:
"Wallace, I believe I can beat you making electric
lights. I don't think you are working in the right
direction." Another date which shows how promptly
the work was resumed is October 14, 1878, when Edison
filed an application for his first lighting patent:
"Improvement in Electric Lights." In after years,
discussing the work of Wallace, who was not only a great
pioneer electrical manufacturer, but one of the founders
of the wire-drawing and brass-working industry,
Edison said: "Wallace was one of the earliest pioneers
in electrical matters in this country. He has
done a great deal of good work, for which others have
received the credit; and the work which he did in
the early days of electric lighting others have benefited
by largely, and he has been crowded to one side
and forgotten." Associated in all this work with
Wallace at Ansonia was Prof. Moses G. Farmer,
famous for the introduction of the fire-alarm system;
as the discoverer of the self-exciting principle of the
modern dynamo; as a pioneer experimenter in the
electric-railway field; as a telegraph engineer, and
as a lecturer on mines and explosives to naval classes
at Newport. During 1858, Farmer, who, like Edison,
was a ceaseless investigator, had made a series of
studies upon the production of light by electricity,
and had even invented an automatic regulator by
which a number of platinum lamps in multiple arc
could be kept at uniform voltage for any length of
time. In July, 1859, he lit up one of the rooms of
his house at Salem, Massachusetts, every evening
with such lamps, using in them small pieces of platinum
and iridium wire, which were made to incandesce
by means of current from primary batteries.
Farmer was not one of the party that memorable day
in September, but his work was known through his
intimate connection with Wallace, and there is no
doubt that reference was made to it. Such work had
not led very far, the "lamps" were hopelessly short-
lived, and everything was obviously experimental;
but it was all helpful and suggestive to one whose
open mind refused no hint from any quarter.

At the commencement of his new attempts, Edison
returned to his experiments with carbon as an
incandescent burner for a lamp, and made a very large
number of trials, all in vacuo. Not only were the
ordinary strip paper carbons tried again, but tissue-
paper coated with tar and lampblack was rolled
into thin sticks, like knitting-needles, carbonized and
raised to incandescence in vacuo. Edison also tried
hard carbon, wood carbons, and almost every
conceivable variety of paper carbon in like manner.
With the best vacuum that he could then get by
means of the ordinary air-pump, the carbons would
last, at the most, only from ten to fifteen minutes in
a state of incandescence. Such results were evidently
not of commercial value.

Edison then turned his attention in other directions.
In his earliest consideration of the problem
of subdividing the electric current, he had decided
that the only possible solution lay in the employment
of a lamp whose incandescing body should have a
high resistance combined with a small radiating surface,
and be capable of being used in what is called
"multiple arc," so that each unit, or lamp, could be
turned on or off without interfering with any other
unit or lamp. No other arrangement could possibly
be considered as commercially practicable.

The full significance of the three last preceding
sentences will not be obvious to laymen, as undoubtedly
many of the readers of this book may be; and now
being on the threshold of the series of Edison's experiments
that led up to the basic invention, we interpolate
a brief explanation, in order that the reader
may comprehend the logical reasoning and work that
in this case produced such far-reaching results.

If we consider a simple circuit in which a current
is flowing, and include in the circuit a carbon horseshoe-like
conductor which it is desired to bring to
incandescence by the heat generated by the current
passing through it, it is first evident that the resistance
offered to the current by the wires themselves
must be less than that offered by the burner, because,
otherwise current would be wasted as heat in the conducting
wires. At the very foundation of the electric-
lighting art is the essentially commercial consideration
that one cannot spend very much for conductors, and
Edison determined that, in order to use wires of a
practicable size, the voltage of the current (i.e., its
pressure or the characteristic that overcomes resistance
to its flow) should be one hundred and ten volts,
which since its adoption has been the standard. To
use a lower voltage or pressure, while making the solution
of the lighting problem a simple one as we shall
see, would make it necessary to increase the size of
the conducting wires to a prohibitive extent. To
increase the voltage or pressure materially, while
permitting some saving in the cost of conductors, would
enormously increase the difficulties of making a
sufficiently high resistance conductor to secure light by
incandescence. This apparently remote consideration
--weight of copper used--was really the commercial
key to the problem, just as the incandescent
burner was the scientific key to that problem. Before
Edison's invention incandescent lamps had been
suggested as a possibility, but they were provided
with carbon rods or strips of relatively low resistance,
and to bring these to incandescence required a current
of low pressure, because a current of high voltage
would pass through them so readily as not to generate
heat; and to carry a current of low pressure through
wires without loss would require wires of enormous
size.[8] Having a current of relatively high pressure
to contend with, it was necessary to provide a carbon
burner which, as compared with what had previously
been suggested, should have a very great resistance.
Carbon as a material, determined after patient search,
apparently offered the greatest hope, but even with
this substance the necessary high resistance could be
obtained only by making the burner of extremely
small cross-section, thereby also reducing its radiating
surface. Therefore, the crucial point was the
production of a hair-like carbon filament, with a
relatively great resistance and small radiating surface,
capable of withstanding mechanical shock, and
susceptible of being maintained at a temperature of
over two thousand degrees for a thousand hours or
more before breaking. And this filamentary conductor
required to be supported in a vacuum chamber
so perfectly formed and constructed that during all
those hours, and subjected as it is to varying temperatures,
not a particle of air should enter to disintegrate
the filament. And not only so, but the
lamp after its design must not be a mere laboratory
possibility, but a practical commercial article capable
of being manufactured at low cost and in large
quantities. A statement of what had to be done in
those days of actual as well as scientific electrical
darkness is quite sufficient to explain Tyndall's attitude
of mind in preferring that the problem should
be in Edison's hands rather than in his own. To
say that the solution of the problem lay merely in
reducing the size of the carbon burner to a mere hair,
is to state a half-truth only; but who, we ask, would
have had the temerity even to suggest that such an
attenuated body could be maintained at a white heat,
without disintegration, for a thousand hours? The solution
consisted not only in that, but in the enormous
mass of patiently worked-out details--the manufacture
of the filaments, their uniform carbonization,
making the globes, producing a perfect vacuum, and
countless other factors, the omission of any one of
which would probably have resulted eventually in

[8] As a practical illustration of these facts it was calculated by
Professor Barker, of the University of Pennsylvania (after Edison
had invented the incandescent lamp), that if it should cost $100,000
for copper conductors to supply current to Edison lamps in
a given area, it would cost about $200,000,000 for copper conductors
for lighting the same area by lamps of the earlier experimenters
--such, for instance, as the lamp invented by Konn in 1875. This
enormous difference would be accounted for by the fact that
Edison's lamp was one having a high resistance and relatively
small radiating surface, while Konn's lamp was one having a very
low resistance and large radiating surface.

Continuing the digression one step farther in order
to explain the term "multiple arc," it may be stated
that there are two principal systems
of distributing electric current, one
termed "series," and the other
"multiple arc." The two are
illustrated, diagrammatically,
side by side, the
arrows indicating flow of
current. The series system,
it will be seen, presents
one continuous path
for the current. The current
for the last lamp
must pass through the
first and all the intermediate
lamps. Hence, if
any one light goes out,
the continuity of the path
is broken, current cannot
flow, and all the lamps
are extinguished unless a
loop or by-path is provided. It is quite
obvious that such a system would be
commercially impracticable where small
units, similar to gas jets, were employed. On the other
hand, in the multiple-arc system, current may be considered
as flowing in two parallel conductors like the
vertical sides of a ladder, the ends of which never
come together. Each lamp is placed in a separate
circuit across these two conductors, like a rung in
the ladder, thus making a separate and independent
path for the current in each case. Hence, if
a lamp goes out, only that individual subdivision, or
ladder step, is affected; just that one particular path
for the current is interrupted, but none of the other
lamps is interfered with. They remain lighted, each
one independent of the other. The reader will quite
readily understand, therefore, that a multiple-arc system
is the only one practically commercial where
electric light is to be used in small units like those
of gas or oil.

Such was the nature of the problem that confronted
Edison at the outset. There was nothing in the
whole world that in any way approximated a solution,
although the most brilliant minds in the electrical
art had been assiduously working on the subject
for a quarter of a century preceding. As already seen,
he came early to the conclusion that the only solution
lay in the use of a lamp of high resistance and
small radiating surface, and, with characteristic fervor
and energy, he attacked the problem from this
standpoint, having absolute faith in a successful outcome.
The mere fact that even with the successful
production of the electric lamp the assault on the
complete problem of commercial lighting would hardly
be begun did not deter him in the slightest. To
one of Edison's enthusiastic self-confidence the long
vista of difficulties ahead--we say it in all sincerity--
must have been alluring.

After having devoted several months to experimental
trials of carbon, at the end of 1878, as already
detailed, he turned his attention to the platinum
group of metals and began a series of experiments in
which he used chiefly platinum wire and iridium wire,
and alloys of refractory metals in the form of wire burners
for incandescent lamps. These metals have very
high fusing-points, and were found to last longer than
the carbon strips previously used when heated up to
incandescence by the electric current, although under
such conditions as were then possible they were
melted by excess of current after they had been
lighted a comparatively short time, either in the
open air or in such a vacuum as could be obtained
by means of the ordinary air-pump.

Nevertheless, Edison continued along this line of
experiment with unremitting vigor, making improvement
after improvement, until about April, 1879, he
devised a means whereby platinum wire of a given
length, which would melt in the open air when giving
a light equal to four candles, would emit a light of
twenty-five candle-power without fusion. This was
accomplished by introducing the platinum wire into
an all-glass globe, completely sealed and highly
exhausted of air, and passing a current through the
platinum wire while the vacuum was being made. In
this, which was a new and radical invention, we see
the first step toward the modern incandescent lamp.
The knowledge thus obtained that current passing
through the platinum during exhaustion would drive
out occluded gases (i.e., gases mechanically held in
or upon the metal), and increase the infusibility of
the platinum, led him to aim at securing greater perfection
in the vacuum, on the theory that the higher
the vacuum obtained, the higher would be the infusibility
of the platinum burner. And this fact also
was of the greatest importance in making successful
the final use of carbon, because without the subjection
of the carbon to the heating effect of current during
the formation of the vacuum, the presence of occluded
gases would have been a fatal obstacle.

Continuing these experiments with most fervent
zeal, taking no account of the passage of time, with
an utter disregard for meals, and but scanty hours
of sleep snatched reluctantly at odd periods of the
day or night, Edison kept his laboratory going without
cessation. A great variety of lamps was made
of the platinum-iridium type, mostly with thermal
devices to regulate the temperature of the burner and
prevent its being melted by an excess of current.
The study of apparatus for obtaining more perfect
vacua was unceasingly carried on, for Edison realized
that in this there lay a potent factor of ultimate
success. About August he had obtained a pump that
would produce a vacuum up to about the one-hundred-
thousandth part of an atmosphere, and some
time during the next month, or beginning of October,
had obtained one that would produce a vacuum up
to the one-millionth part of an atmosphere. It must
be remembered that the conditions necessary for
MAINTAINING this high vacuum were only made possible
by his invention of the one-piece all-glass globe,
in which all the joints were hermetically sealed
during its manufacture into a lamp, whereby a high
vacuum could be retained continuously for any
length of time.

In obtaining this perfection of vacuum apparatus,
Edison realized that he was approaching much nearer
to a solution of the problem. In his experiments with
the platinum-iridium lamps, he had been working all
the time toward the proposition of high resistance
and small radiating surface, until he had made a
lamp having thirty feet of fine platinum wire wound
upon a small bobbin of infusible material; but the
desired economy, simplicity, and durability were not
obtained in this manner, although at all times the
burner was maintained at a critically high temperature.
After attaining a high degree of perfection
with these lamps, he recognized their impracticable
character, and his mind reverted to the opinion he
had formed in his early experiments two years before
--viz., that carbon had the requisite resistance to
permit a very simple conductor to accomplish the
object if it could be used in the form of a hair-like
"filament," provided the filament itself could be
made sufficiently homogeneous. As we have already
seen, he could not use carbon successfully in his
earlier experiments, for the strips of carbon he then
employed, although they were much larger than
"filaments," would not stand, but were consumed in
a few minutes under the imperfect conditions then
at his command.

Now, however, that he had found means for obtaining
and maintaining high vacua, Edison immediately
went back to carbon, which from the first he
had conceived of as the ideal substance for a burner.
His next step proved conclusively the correctness of
his old deductions. On October 21, 1879, after many
patient trials, he carbonized a piece of cotton sewing-
thread bent into a loop or horseshoe form, and had it
sealed into a glass globe from which he exhausted the air
until a vacuum up to one-millionth of an atmosphere
was produced. This lamp, when put on the circuit,
lighted up brightly to incandescence and maintained
its integrity for over forty hours, and lo! the practical
incandescent lamp was born. The impossible, so
called, had been attained; subdivision of the electric-
light current was made practicable; the goal had
been reached; and one of the greatest inventions of
the century was completed. Up to this time Edison
had spent over $40,000 in his electric-light experiments,
but the results far more than justified the expenditure,
for with this lamp he made the discovery
that the FILAMENT of carbon, under the conditions of
high vacuum, was commercially stable and would
stand high temperatures without the disintegration
and oxidation that took place in all previous attempts
that he knew of for making an incandescent
burner out of carbon. Besides, this lamp possessed
the characteristics of high resistance and small radiating
surface, permitting economy in the outlay for
conductors, and requiring only a small current for
each unit of light--conditions that were absolutely
necessary of fulfilment in order to accomplish commercially
the subdivision of the electric-light current.

This slender, fragile, tenuous thread of brittle carbon,
glowing steadily and continuously with a soft
light agreeable to the eyes, was the tiny key that
opened the door to a world revolutionized in its interior
illumination. It was a triumphant vindication
of Edison's reasoning powers, his clear perceptions,
his insight into possibilities, and his inventive faculty,
all of which had already been productive of so many
startling, practical, and epoch-making inventions.
And now he had stepped over the threshold of a new
art which has since become so world-wide in its application
as to be an integral part of modern human

[9] The following extract from Walker on Patents (4th edition)
will probably be of interest to the reader:

"Sec. 31a. A meritorious exception, to the rule of the last
section, is involved in the adjudicated validity of the Edison
incandescent-light patent. The carbon filament, which constitutes
the only new part of the combination of the second
claim of that patent, differs from the earlier carbon burners of
Sawyer and Man, only in having a diameter of one-sixty-fourth
of an inch or less, whereas the burners of Sawyer and Man had a
diameter of one-thirty-second of an inch or more. But that reduction
of one-half in diameter increased the resistance of the
burner FOURFOLD, and reduced its radiating surface TWOFOLD, and
thus increased eightfold, its ratio of resistance to radiating surface.
That eightfold increase of proportion enabled the resistance
of the conductor of electricity from the generator to
the burner to be increased eightfold, without any increase of
percentage of loss of energy in that conductor, or decrease of
percentage of development of heat in the burner; and thus enabled
the area of the cross-section of that conductor to be reduced
eightfold, and thus to be made with one-eighth of the amount of
copper or other metal, which would be required if the reduction
of diameter of the burner from one-thirty-second to one-sixty-
fourth of an inch had not been made. And that great reduction
in the size and cost of conductors, involved also a great difference
in the composition of the electric energy employed in the system;
that difference consisting in generating the necessary amount of
electrical energy with comparatively high electromotive force,
and comparatively low current, instead of contrariwise. For this
reason, the use of carbon filaments, one-sixty-fourth of an inch in
diameter or less, instead of carbon burners one-thirty-second of
an inch in diameter or more, not only worked an enormous economy
in conductors, but also necessitated a great change in generators,
and did both according to a philosophy, which Edison
was the first to know, and which is stated in this paragraph in its
simplest form and aspect, and which lies at the foundation of the
incandescent electric lighting of the world."

No sooner had the truth of this new principle been
established than the work to establish it firmly and
commercially was carried on more assiduously than
ever. The next immediate step was a further
investigation of the possibilities of improving the
quality of the carbon filament. Edison had previously
made a vast number of experiments with carbonized
paper for various electrical purposes, with
such good results that he once more turned to it and
now made fine filament-like loops of this material
which were put into other lamps. These proved
even more successful (commercially considered) than
the carbonized thread--so much so that after a number
of such lamps had been made and put through
severe tests, the manufacture of lamps from these
paper carbons was begun and carried on continuously.
This necessitated first the devising and making of a
large number of special tools for cutting the carbon
filaments and for making and putting together the
various parts of the lamps. Meantime, great excitement
had been caused in this country and in Europe
by the announcement of Edison's success. In the
Old World, scientists generally still declared the
impossibility of subdividing the electric-light current,
and in the public press Mr. Edison was denounced as
a dreamer. Other names of a less complimentary
nature were applied to him, even though his lamp
were actually in use, and the principle of commercial
incandescent lighting had been established.

Between October 21, 1879, and December 21, 1879,
some hundreds of these paper-carbon lamps had been
made and put into actual use, not only in the laboratory,
but in the streets and several residences at
Menlo Park, New Jersey, causing great excitement
and bringing many visitors from far and near. On
the latter date a full-page article appeared in the
New York Herald which so intensified the excited
feeling that Mr. Edison deemed it advisable to make
a public exhibition. On New Year's Eve, 1879,
special trains were run to Menlo Park by the Pennsylvania
Railroad, and over three thousand persons
took advantage of the opportunity to go out there
and witness this demonstration for themselves. In
this great crowd were many public officials and men
of prominence in all walks of life, who were enthusiastic
in their praises.

In the mean time, the mind that conceived and
made practical this invention could not rest content
with anything less than perfection, so far as it could
be realized. Edison was not satisfied with paper
carbons. They were not fully up to the ideal that
he had in mind. What he sought was a perfectly
uniform and homogeneous carbon, one like the "One-
Hoss Shay," that had no weak spots to break down
at inopportune times. He began to carbonize everything
in nature that he could lay hands on. In his
laboratory note-books are innumerable jottings of the
things that were carbonized and tried, such as tissue-
paper, soft paper, all kinds of cardboards, drawing-
paper of all grades, paper saturated with tar, all kinds
of threads, fish-line, threads rubbed with tarred lampblack,
fine threads plaited together in strands, cotton
soaked in boiling tar, lamp-wick, twine, tar and
lampblack mixed with a proportion of lime, vulcanized
fibre, celluloid, boxwood, cocoanut hair and
shell, spruce, hickory, baywood, cedar and maple
shavings, rosewood, punk, cork, bagging, flax, and
a host of other things. He also extended his searches
far into the realms of nature in the line of grasses,
plants, canes, and similar products, and in these
experiments at that time and later he carbonized, made
into lamps, and tested no fewer than six thousand
different species of vegetable growths.

The reasons for such prodigious research are not
apparent on the face of the subject, nor is this the
occasion to enter into an explanation, as that alone
would be sufficient to fill a fair-sized book. Suffice it
to say that Edison's omnivorous reading, keen observation,
power of assimilating facts and natural
phenomena, and skill in applying the knowledge thus
attained to whatever was in hand, now came into full
play in determining that the results he desired could
only be obtained in certain directions.

At this time he was investigating everything with
a microscope, and one day in the early part of 1880
he noticed upon a table in the laboratory an ordinary
palm-leaf fan. He picked it up and, looking it
over, observed that it had a binding rim made of
bamboo, cut from the outer edge of the cane; a very
long strip. He examined this, and then gave it to
one of his assistants, telling him to cut it up and get
out of it all the filaments he could, carbonize them,
put them into lamps, and try them. The results of
this trial were exceedingly successful, far better than
with anything else thus far used; indeed, so much so,
that after further experiments and microscopic
examinations Edison was convinced that he was now on
the right track for making a thoroughly stable,
commercial lamp; and shortly afterward he sent a man
to Japan to procure further supplies of bamboo. The
fascinating story of the bamboo hunt will be told
later; but even this bamboo lamp was only one item
of a complete system to be devised--a system that
has since completely revolutionized the art of interior

Reference has been made in this chapter to the
preliminary study that Edison brought to bear on
the development of the gas art and industry. This
study was so exhaustive that one can only compare it
to the careful investigation made in advance by any
competent war staff of the elements of strength and
weakness, on both sides, in a possible campaign. A
popular idea of Edison that dies hard, pictures a
breezy, slap-dash, energetic inventor arriving at new
results by luck and intuition, making boastful
assertions and then winning out by mere chance. The
native simplicity of the man, the absence of pose and
ceremony, do much to strengthen this notion; but
the real truth is that while gifted with unusual imagination,
Edison's march to the goal of a new invention
is positively humdrum and monotonous in its
steady progress. No one ever saw Edison in a hurry;
no one ever saw him lazy; and that which he did with
slow, careful scrutiny six months ago, he will be doing
with just as much calm deliberation of research six
months hence--and six years hence if necessary. If,
for instance, he were asked to find the most perfect
pebble on the Atlantic shore of New Jersey, instead
of hunting here, there, and everywhere for the desired
object, we would no doubt find him patiently
screening the entire beach, sifting out the most perfect
stones and eventually, by gradual exclusion,
reaching the long-sought-for pebble; and the mere
fact that in this search years might be taken, would
not lessen his enthusiasm to the slightest extent.

In the "prospectus book" among the series of famous
note-books, all the references and data apply to
gas. The book is numbered 184, falls into the period
now dealt with, and runs along casually with items
spread out over two or three years. All these notes
refer specifically to "Electricity vs. Gas as General
Illuminants," and cover an astounding range of inquiry
and comment. One of the very first notes tells
the whole story: "Object, Edison to effect exact
imitation of all done by gas, so as to replace lighting
by gas by lighting by electricity. To improve the
illumination to such an extent as to meet all requirements
of natural, artificial, and commercial conditions."
A large programme, but fully executed!
The notes, it will be understood, are all in Edison's
handwriting. They go on to observe that "a general
system of distribution is the only possible means of
economical illumination," and they dismiss isolated-
plant lighting as in mills and factories as of so little
importance to the public--"we shall leave the con-
sideration of this out of this book." The shrewd
prophecy is made that gas will be manufactured less
for lighting, as the result of electrical competition,
and more and more for heating, etc., thus enlarging
its market and increasing its income. Comment is
made on kerosene and its cost, and all kinds of general
statistics are jotted down as desirable. Data are
to be obtained on lamp and dynamo efficiency, and
"Another review of the whole thing as worked out
upon pure science principles by Rowland, Young,
Trowbridge; also Rowland on the possibilities and
probabilities of cheaper production by better
manufacture--higher incandescence without decrease of
life of lamps." Notes are also made on meters and
motors. "It doesn't matter if electricity is used for
light or for power"; while small motors, it is observed,
can be used night or day, and small steam-engines are
inconvenient. Again the shrewd comment: "Generally
poorest district for light, best for power, thus
evening up whole city--the effect of this on investment."

It is pointed out that "Previous inventions failed--
necessities for commercial success and accomplishment
by Edison. Edison's great effort--not to make
a large light or a blinding light, but a small light
having the mildness of gas." Curves are then called
for of iron and copper investment--also energy
line--curves of candle-power and electromotive force;
curves on motors; graphic representation of the
consumption of gas January to December; tables and
formulae; representations graphically of what one
dollar will buy in different kinds of light; "table,
weight of copper required different distance, 100-ohm
lamp, 16 candles"; table with curves showing increased
economy by larger engine, higher power, etc.
There is not much that is dilettante about all this.
Note is made of an article in April, 1879, putting the
total amount of gas investment in the whole world
at that time at $1,500,000,000; which is now (1910)
about the amount of the electric-lighting investment
in the United States. Incidentally a note remarks:
"So unpleasant is the effect of the products of gas
that in the new Madison Square Theatre every gas
jet is ventilated by special tubes to carry away the
products of combustion." In short, there is no aspect
of the new problem to which Edison failed to apply
his acutest powers; and the speed with which the
new system was worked out and introduced was
simply due to his initial mastery of all the factors in
the older art. Luther Stieringer, an expert gas engineer
and inventor, whose services were early enlisted,
once said that Edison knew more about gas
than any other man he had ever met. The remark
is an evidence of the kind of preparation Edison gave
himself for his new task.



FROM the spring of 1876 to 1886 Edison lived and
did his work at Menlo Park; and at this stage
of the narrative, midway in that interesting and
eventful period, it is appropriate to offer a few notes
and jottings on the place itself, around which tradition
is already weaving its fancies, just as at the time
the outpouring of new inventions from it invested
the name with sudden prominence and with the
glamour of romance. "In 1876 I moved," says Edison,
"to Menlo Park, New Jersey, on the Pennsylvania
Railroad, several miles below Elizabeth. The
move was due to trouble I had about rent. I had
rented a small shop in Newark, on the top floor of
a padlock factory, by the month. I gave notice that
I would give it up at the end of the month, paid the
rent, moved out, and delivered the keys. Shortly
afterward I was served with a paper, probably a
judgment, wherein I was to pay nine months' rent.
There was some law, it seems, that made a monthly
renter liable for a year. This seemed so unjust that I
determined to get out of a place that permitted such
injustice." For several Sundays he walked through
different parts of New Jersey with two of his assistants
before he decided on Menlo Park. The change was
a fortunate one, for the inventor had married Miss
Mary E. Stillwell, and was now able to establish himself
comfortably with his wife and family while enjoying
immediate access to the new laboratory. Every
moment thus saved was valuable.

To-day the place and region have gone back to the
insignificance from which Edison's genius lifted them
so startlingly. A glance from the car windows
reveals only a gently rolling landscape dotted with
modest residences and unpretentious barns; and
there is nothing in sight by way of memorial to suggest
that for nearly a decade this spot was the scene
of the most concentrated and fruitful inventive activity
the world has ever known. Close to the Menlo Park
railway station is a group of gaunt and deserted buildings,
shelter of the casual tramp, and slowly crumbling
away when not destroyed by the carelessness of
some ragged smoker. This silent group of buildings
comprises the famous old laboratory and workshops
of Mr. Edison, historic as being the birthplace of the
carbon transmitter, the phonograph, the incandescent
lamp, and the spot where Edison also worked
out his systems of electrical distribution, his
commercial dynamo, his electric railway, his megaphone,
his tasimeter, and many other inventions of greater
or lesser degree. Here he continued, moreover, his
earlier work on the quadruplex, sextuplex, multiplex,
and automatic telegraphs, and did his notable pioneer
work in wireless telegraphy. As the reader knows,
it had been a master passion with Edison from boyhood
up to possess a laboratory, in which with free
use of his own time and powers, and with command
of abundant material resources, he could wrestle with
Nature and probe her closest secrets. Thus, from the
little cellar at Port Huron, from the scant shelves in
a baggage car, from the nooks and corners of dingy
telegraph offices, and the grimy little shops in New
York and Newark, he had now come to the proud
ownership of an establishment to which his favorite
word "laboratory" might justly be applied. Here
he could experiment to his heart's content and invent
on a larger, bolder scale than ever--and he did!

Menlo Park was the merest hamlet. Omitting the
laboratory structures, it had only about seven houses,
the best looking of which Edison lived in, a place that
had a windmill pumping water into a reservoir. One
of the stories of the day was that Edison had his
front gate so connected with the pumping plant that
every visitor as he opened or closed the gate added
involuntarily to the supply in the reservoir. Two or
three of the houses were occupied by the families of
members of the staff; in the others boarders were
taken, the laboratory, of course, furnishing all the
patrons. Near the railway station was a small
saloon kept by an old Scotchman named Davis,
where billiards were played in idle moments, and
where in the long winter evenings the hot stove was
a centre of attraction to loungers and story-tellers.
The truth is that there was very little social life of
any kind possible under the strenuous conditions prevailing
at the laboratory, where, if anywhere, relaxation
was enjoyed at odd intervals of fatigue and waiting.

The main laboratory was a spacious wooden building
of two floors. The office was in this building at
first, until removed to the brick library when that
was finished. There S. L. Griffin, an old telegraph
friend of Edison, acted as his secretary and had charge
of a voluminous and amazing correspondence. The
office employees were the Carman brothers and the
late John F. Randolph, afterwards secretary. According
to Mr. Francis Jehl, of Budapest, then one of the
staff, to whom the writers are indebted for a great
deal of valuable data on this period: "It was on the
upper story of this laboratory that the most important
experiments were executed, and where the incandescent
lamp was born. This floor consisted of a
large hall containing several long tables, upon which
could be found all the various instruments, scientific
and chemical apparatus that the arts at that time
could produce. Books lay promiscuously about,
while here and there long lines of bichromate-of-
potash cells could be seen, together with experimental
models of ideas that Edison or his assistants were
engaged upon. The side walls of this hall were lined
with shelves filled with bottles, phials, and other
receptacles containing every imaginable chemical and
other material that could be obtained, while at the
end of this hall, and near the organ which stood in
the rear, was a large glass case containing the world's
most precious metals in sheet and wire form, together
with very rare and costly chemicals. When evening
came on, and the last rays of the setting sun penetrated
through the side windows, this hall looked like
a veritable Faust laboratory.

"On the ground floor we had our testing-table,
which stood on two large pillars of brick built deep
into the earth in order to get rid of all vibrations on
account of the sensitive instruments that were upon
it. There was the Thomson reflecting mirror galvanometer
and electrometer, while nearby were the
standard cells by which the galvanometers were
adjusted and standardized. This testing-table was
connected by means of wires with all parts of the
laboratory and machine-shop, so that measurements
could be conveniently made from a distance, as in
those days we had no portable and direct-reading
instruments, such as now exist. Opposite this table we
installed, later on, our photometrical chamber, which
was constructed on the Bunsen principle. A little
way from this table, and separated by a partition,
we had the chemical laboratory with its furnaces and
stink-chambers. Later on another chemical laboratory
was installed near the photometer-room, and this
Dr. A. Haid had charge of."

Next to the laboratory in importance was the machine-
shop, a large and well-lighted building of brick,
at one end of which there was the boiler and engine-
room. This shop contained light and heavy lathes,
boring and drilling machines, all kinds of planing
machines; in fact, tools of all descriptions, so that
any apparatus, however delicate or heavy, could be
made and built as might be required by Edison in
experimenting. Mr. John Kruesi had charge of this
shop, and was assisted by a number of skilled mechanics,
notably John Ott, whose deft fingers and
quick intuitive grasp of the master's ideas are still
in demand under the more recent conditions at the
Llewellyn Park laboratory in Orange.

Between the machine-shop and the laboratory was
a small building of wood used as a carpenter-shop,
where Tom Logan plied his art. Nearby was the
gasoline plant. Before the incandescent lamp was
perfected, the only illumination was from gasoline
gas; and that was used later for incandescent-lamp
glass-blowing, which was done in another small building
on one side of the laboratory. Apparently little
or no lighting service was obtained from the Wallace-
Farmer arc lamps secured from Ansonia, Connecticut.
The dynamo was probably needed for Edison's own

On the outskirts of the property was a small building
in which lampblack was crudely but carefully
manufactured and pressed into very small cakes, for
use in the Edison carbon transmitters of that time.
The night-watchman, Alfred Swanson, took care of
this curious plant, which consisted of a battery of
petroleum lamps that were forced to burn to the
sooting point. During his rounds in the night Swanson
would find time to collect from the chimneys the
soot that the lamps gave. It was then weighed out
into very small portions, which were pressed into
cakes or buttons by means of a hand-press. These
little cakes were delicately packed away between
layers of cotton in small, light boxes and shipped to
Bergmann in New York, by whom the telephone
transmitters were being made. A little later the Edison
electric railway was built on the confines of the
property out through the woods, at first only a third
of a mile in length, but reaching ultimately to Pumptown,
almost three miles away.

Mr. Edison's own words may be quoted as to the
men with whom he surrounded himself here and
upon whose services he depended principally for help
in the accomplishment of his aims. In an autobiographical
article in the Electrical World of March 5,
1904, he says: "It is interesting to note that in
addition to those mentioned above (Charles Batchelor
and Frank Upton), I had around me other men who
ever since have remained active in the field, such as
Messrs. Francis Jehl, William J. Hammer, Martin
Force, Ludwig K. Boehm, not forgetting that good
friend and co-worker, the late John Kruesi. They
found plenty to do in the various developments of
the art, and as I now look back I sometimes wonder
how we did so much in so short a time." Mr. Jehl
in his reminiscences adds another name to the above
--namely, that of John W. Lawson, and then goes on
to say: "These are the names of the pioneers of
incandescent lighting, who were continuously at the
side of Edison day and night for some years, and who,
under his guidance, worked upon the carbon-filament
lamp from its birth to ripe maturity. These men all
had complete faith in his ability and stood by him
as on a rock, guarding their work with the secretiveness
of a burglar-proof safe. Whenever it leaked out
in the world that Edison was succeeding in his work on
the electric light, spies and others came to the Park;
so it was of the utmost importance that the experiments
and their results should be kept a secret until
Edison had secured the protection of the Patent
Office." With this staff was associated from the first
Mr. E. H. Johnson, whose work with Mr. Edison lay
chiefly, however, outside the laboratory, taking him
to all parts of the country and to Europe. There were
also to be regarded as detached members of it the
Bergmann brothers, manufacturing for Mr. Edison in
New York, and incessantly experimenting for him.
In addition there must be included Mr. Samuel Insull,
whose activities for many years as private secretary
and financial manager were devoted solely to Mr.
Edison's interests, with Menlo Park as a centre and
main source of anxiety as to pay-rolls and other
constantly recurring obligations. The names of yet
other associates occur from time to time in this
narrative--"Edison men" who have been very proud
of their close relationship to the inventor and his
work at old Menlo. "There was also Mr. Charles L.
Clarke, who devoted himself mainly to engineering
matters, and later on acted as chief engineer of the
Edison Electric Light Company for some years.
Then there were William Holzer and James Hipple,
both of whom took an active part in the practical
development of the glass-blowing department of the
laboratory, and, subsequently, at the first Edison
lamp factory at Menlo Park. Later on Messrs. Jehl,
Hipple, and Force assisted Mr. Batchelor to install
the lamp-works of the French Edison Company at
Ivry-sur-Seine. Then there were Messrs. Charles T.
Hughes, Samuel D. Mott, and Charles T. Mott, who
devoted their time chiefly to commercial affairs. Mr.
Hughes conducted most of this work, and later on took
a prominent part in Edison's electric-railway
experiments. His business ability was on a high level,
while his personal character endeared him to us all.

Among other now well-known men who came to us
and assisted in various kinds of work were Messrs.
Acheson, Worth, Crosby, Herrick, and Hill, while
Doctor Haid was placed by Mr. Edison in charge of
a special chemical laboratory. Dr. E. L. Nichols
was also with us for a short time conducting a special
series of experiments. There was also Mr. Isaacs,
who did a great deal of photographic work, and to
whom we must be thankful for the pictures of Menlo
Park in connection with Edison's work.

"Among others who were added to Mr. Kruesi's
staff in the machine-shop were Messrs. J. H. Vail and
W. S. Andrews. Mr. Vail had charge of the dynamo-
room. He had a good general knowledge of machinery,
and very soon acquired such familiarity with the
dynamos that he could skip about among them with
astonishing agility to regulate their brushes or to
throw rosin on the belts when they began to squeal.
Later on he took an active part in the affairs and
installations of the Edison Light Company. Mr.
Andrews stayed on Mr. Kruesi's staff as long as the
laboratory machine-shop was kept open, after which
he went into the employ of the Edison Electric Light
Company and became actively engaged in the commercial
and technical exploitation of the system.
Another man who was with us at Menlo Park was Mr.
Herman Claudius, an Austrian, who at one time was
employed in connection with the State Telegraphs of
his country. To him Mr. Edison assigned the task
of making a complete model of the network of
conductors for the contemplated first station in New

Mr. Francis R. Upton, who was early employed by
Mr. Edison as his mathematician, furnishes a pleasant,
vivid picture of his chief associates engaged on
the memorable work at Menlo Park. He says: "Mr.
Charles Batchelor was Mr. Edison's principal assistant
at that time. He was an Englishman, and came
to this country to set up the thread-weaving machinery
for the Clark thread-works. He was a most
intelligent, patient, competent, and loyal assistant to
Mr. Edison. I remember distinctly seeing him work
many hours to mount a small filament; and his hand
would be as steady and his patience as unyielding at
the end of those many hours as it was at the beginning,
in spite of repeated failures. He was a wonderful
mechanic; the control that he had of his fingers
was marvellous, and his eyesight was sharp. Mr.
Batchelor's judgment and good sense were always
in evidence.

"Mr. Kruesi was the superintendent, a Swiss trained
in the best Swiss ideas of accuracy. He was a splendid
mechanic with a vigorous temper, and wonderful
ability to work continuously and to get work out of
men. It was an ideal combination, that of Edison,
Batchelor, and Kruesi. Mr. Edison with his wonderful
flow of ideas which were sharply defined in his
mind, as can be seen by any of the sketches that he
made, as he evidently always thinks in three dimensions;
Mr. Kruesi, willing to take the ideas, and
capable of comprehending them, would distribute
the work so as to get it done with marvellous quickness
and great accuracy. Mr. Batchelor was always
ready for any special fine experimenting or observa-
tion, and could hold to whatever he was at as long
as Mr. Edison wished; and always brought to bear
on what he was at the greatest skill."

While Edison depended upon Upton for his mathematical
work, he was wont to check it up in a very
practical manner, as evidenced by the following incident
described by Mr. Jehl: "I was once with Mr.
Upton calculating some tables which he had put me
on, when Mr. Edison appeared with a glass bulb
having a pear-shaped appearance in his hand. It was
the kind that we were going to use for our lamp
experiments; and Mr. Edison asked Mr. Upton to
please calculate for him its cubic contents in centimetres.
Now Mr. Upton was a very able mathematician,
who, after he finished his studies at Princeton,
went to Germany and got his final gloss under
that great master, Helmholtz. Whatever he did and
worked on was executed in a pure mathematical
manner, and any wrangler at Oxford would have been
delighted to see him juggle with integral and differential
equations, with a dexterity that was surprising.
He drew the shape of the bulb exactly on paper,
and got the equation of its lines with which he was
going to calculate its contents, when Mr. Edison again
appeared and asked him what it was. He showed
Edison the work he had already done on the subject,
and told him that he would very soon finish calculating
it. `Why,' said Edison, `I would simply take
that bulb and fill it with mercury and weigh it; and
from the weight of the mercury and its specific gravity
I'll get it in five minutes, and use less mental energy
than is necessary in such a fatiguing operation.' "

Menlo Park became ultimately the centre of Edison's
business life as it was of his inventing. After
the short distasteful period during the introduction
of his lighting system, when he spent a large part of
his time at the offices at 65 Fifth Avenue, New York,
or on the actual work connected with the New York
Edison installation, he settled back again in Menlo
Park altogether. Mr. Samuel Insull describes the
business methods which prevailed throughout the
earlier Menlo Park days of "storm and stress," and
the curious conditions with which he had to deal as
private secretary: "I never attempted to systematize
Edison's business life. Edison's whole method
of work would upset the system of any office. He
was just as likely to be at work in his laboratory at
midnight as midday. He cared not for the hours of
the day or the days of the week. If he was exhausted
he might more likely be asleep in the middle of the
day than in the middle of the night, as most of his
work in the way of inventions was done at night. I
used to run his office on as close business methods as
my experience admitted; and I would get at him
whenever it suited his convenience. Sometimes he
would not go over his mail for days at a time; but
other times he would go regularly to his office in the
morning. At other times my engagements used to
be with him to go over his business affairs at Menlo
Park at night, if I was occupied in New York during
the day. In fact, as a matter of convenience I used
more often to get at him at night, as it left my days
free to transact his affairs, and enabled me, probably
at a midnight luncheon, to get a few minutes of his
time to look over his correspondence and get his
directions as to what I should do in some particular
negotiation or matter of finance. While it was a
matter of suiting Edison's convenience as to when I
should transact business with him, it also suited my
own ideas, as it enabled me after getting through my
business with him to enjoy the privilege of watching
him at his work, and to learn something about the
technical side of matters. Whatever knowledge I
may have of the electric light and power industry I
feel I owe it to the tuition of Edison. He was about
the most willing tutor, and I must confess that he
had to be a patient one."

Here again occurs the reference to the incessant
night-work at Menlo Park, a note that is struck in
every reminiscence and in every record of the time.
But it is not to be inferred that the atmosphere of
grim determination and persistent pursuit of the new
invention characteristic of this period made life a
burden to the small family of laborers associated with
Edison. Many a time during the long, weary nights
of experimenting Edison would call a halt for
refreshments, which he had ordered always to be sent
in when night-work was in progress. Everything
would be dropped, all present would join in the meal,
and the last good story or joke would pass around.
In his notes Mr. Jehl says: "Our lunch always ended
with a cigar, and I may mention here that although
Edison was never fastidious in eating, he always
relished a good cigar, and seemed to find in it
consolation and solace.... It often happened that while
we were enjoying the cigars after our midnight re-
past, one of the boys would start up a tune on the
organ and we would all sing together, or one of the
others would give a solo. Another of the boys had
a voice that sounded like something between the ring
of an old tomato can and a pewter jug. He had one
song that he would sing while we roared with laughter.
He was also great in imitating the tin-foil
phonograph.... When Boehm was in good-humor he would
play his zither now and then, and amuse us by singing
pretty German songs. On many of these occasions
the laboratory was the rendezvous of jolly and
convivial visitors, mostly old friends and acquaintances
of Mr. Edison. Some of the office employees
would also drop in once in a while, and as everybody
present was always welcome to partake of the midnight
meal, we all enjoyed these gatherings. After
a while, when we were ready to resume work, our
visitors would intimate that they were going home
to bed, but we fellows could stay up and work, and
they would depart, generally singing some song like
Good-night, ladies! . . . It often happened that when
Edison had been working up to three or four o'clock
in the morning, he would lie down on one of the
laboratory tables, and with nothing but a couple of
books for a pillow, would fall into a sound sleep.
He said it did him more good than being in a soft
bed, which spoils a man. Some of the laboratory
assistants could be seen now and then sleeping on a
table in the early morning hours. If their snoring
became objectionable to those still at work, the
`calmer' was applied. This machine consisted of a
Babbitt's soap box without a cover. Upon it was
mounted a broad ratchet-wheel with a crank, while
into the teeth of the wheel there played a stout,
elastic slab of wood. The box would be placed on
the table where the snorer was sleeping and the crank
turned rapidly. The racket thus produced was something
terrible, and the sleeper would jump up as
though a typhoon had struck the laboratory. The
irrepressible spirit of humor in the old days, although
somewhat strenuous at times, caused many a moment
of hilarity which seemed to refresh the boys, and
enabled them to work with renewed vigor after its
manifestation." Mr. Upton remarks that often during
the period of the invention of the incandescent
lamp, when under great strain and fatigue, Edison
would go to the organ and play tunes in a primitive
way, and come back to crack jokes with the staff.
"But I have often felt that Mr. Edison never could
comprehend the limitations of the strength of other
men, as his own physical and mental strength have
always seemed to be without limit. He could work
continuously as long as he wished, and had sleep at
his command. His sleep was always instant, profound,
and restful. He has told me that he never
dreamed. I have known Mr. Edison now for thirty-one
years, and feel that he has always kept his mind direct
and simple, going straight to the root of troubles.
One of the peculiarities I have noticed is that I have
never known him to break into a conversation going
on around him, and ask what people were talking
about. The nearest he would ever come to it was
when there had evidently been some story told, and
his face would express a desire to join in the laugh,
which would immediately invite telling the story to

Next to those who worked with Edison at the laboratory
and were with him constantly at Menlo Park
were the visitors, some of whom were his business
associates, some of them scientific men, and some of
them hero-worshippers and curiosity-hunters. Foremost
in the first category was Mr. E. H. Johnson,
who was in reality Edison's most intimate friend, and
was required for constant consultation; but whose
intense activity, remarkable grasp of electrical
principles, and unusual powers of exposition, led to his
frequent detachment for long trips, including those
which resulted in the introduction of the telephone,
phonograph, and electric light in England and on
the Continent. A less frequent visitor was Mr. S.
Bergmann, who had all he needed to occupy his time
in experimenting and manufacturing, and whose
contemporaneous Wooster Street letter-heads advertised
Edison's inventions as being made there, Among
the scientists were Prof. George F. Barker, of Philadelphia,
a big, good-natured philosopher, whose valuable
advice Edison esteemed highly. In sharp contrast
to him was the earnest, serious Rowland, of
Johns Hopkins University, afterward the leading
American physicist of his day. Profs. C. F. Brackett
and C. F. Young, of Princeton University, were often
received, always interested in what Edison was doing,
and proud that one of their own students, Mr. Upton,
was taking such a prominent part in the development
of the work.

Soon after the success of the lighting experiments
and the installation at Menlo Park became known,
Edison was besieged by persons from all parts of the
world anxious to secure rights and concessions for
their respective countries. Among these was Mr.
Louis Rau, of Paris, who organized the French Edison
Company, the pioneer Edison lighting corporation
in Europe, and who, with the aid of Mr. Batchelor,
established lamp-works and a machine-shop at Ivry
sur-Seine, near Paris, in 1882. It was there that Mr.
Nikola Tesla made his entree into the field of light
and power, and began his own career as an inventor;
and there also Mr. Etienne Fodor, general manager
of the Hungarian General Electric Company at Budapest,
received his early training. It was he who
erected at Athens the first European Edison station
on the now universal three-wire system. Another
visitor from Europe, a little later, was Mr. Emil
Rathenau, the present director of the great
Allgemeine Elektricitaets Gesellschaft of Germany. He
secured the rights for the empire, and organized the
Berlin Edison system, now one of the largest in the
world. Through his extraordinary energy and enterprise
the business made enormous strides, and Mr.
Rathenau has become one of the most conspicuous
industrial figures in his native country. From Italy
came Professor Colombo, later a cabinet minister,
with his friend Signor Buzzi, of Milan. The rights
were secured for the peninsula; Colombo and his
friends organized the Italian Edison Company, and
erected at Milan the first central station in that
country. Mr. John W. Lieb, Jr., now a vice-president
of the New York Edison Company, was sent
over by Mr. Edison to steer the enterprise technically,
and spent ten years in building it up, with such brilliant
success that he was later decorated as Commander
of the Order of the Crown of Italy by King
Victor. Another young American enlisted into European
service was Mr. E. G. Acheson, the inventor of
carborundum, who built a number of plants in Italy
and France before he returned home. Mr. Lieb has
since become President of the American Institute of
Electrical Engineers and the Association of Edison
Illuminating Companies, while Doctor Acheson has
been President of the American Electrochemical

Switzerland sent Messrs. Turrettini, Biedermann,
and Thury, all distinguished engineers, to negotiate
for rights in the republic; and so it went with regard
to all the other countries of Europe, as well as those
of South America. It was a question of keeping such
visitors away rather than of inviting them to take
up the exploitation of the Edison system; for what
time was not spent in personal interviews was required
for the masses of letters from every country
under the sun, all making inquiries, offering suggestions,
proposing terms. Nor were the visitors merely
those on business bent. There were the lion-hunters
and celebrities, of whom Sarah Bernhardt may serve
as a type. One visit of note was that paid by Lieut.
G. W. De Long, who had an earnest and protracted
conversation with Edison over the Arctic expedition he
was undertaking with the aid of Mr. James Gordon
Bennett, of the New York Herald. The Jeannette was
being fitted out, and Edison told De Long that he
would make and present him with a small dynamo
machine, some incandescent lamps, and an arc lamp.
While the little dynamo was being built all the men
in the laboratory wrote their names on the paper
insulation that was wound upon the iron core of the
armature. As the Jeannette had no steam-engine on
board that could be used for the purpose, Edison
designed the dynamo so that it could be worked by
man power and told Lieutenant De Long "it would
keep the boys warm up in the Arctic," when they
generated current with it. The ill-fated ship never
returned from her voyage, but went down in the icy
waters of the North, there to remain until some
future cataclysm of nature, ten thousand years
hence, shall reveal the ship and the first marine
dynamo as curious relics of a remote civilization.

Edison also furnished De Long with a set of telephones
provided with extensible circuits, so that
parties on the ice-floes could go long distances from
the ship and still keep in communication with her.
So far as the writers can ascertain this is the first
example of "field telephony." Another nautical experiment
that he made at this time, suggested probably
by the requirements of the Arctic expedition,
was a buoy that was floated in New York harbor,
and which contained a small Edison dynamo and two
or three incandescent lamps. The dynamo was
driven by the wave or tide motion through intermediate
mechanism, and thus the lamps were lit up
from time to time, serving as signals. These were the
prototypes of the lighted buoys which have since
become familiar, as in the channel off Sandy Hook.

One notable afternoon was that on which the
New York board of aldermen took a special train out
to Menlo Park to see the lighting system with its
conductors underground in operation. The Edison Electric
Illuminating Company was applying for a franchise,
and the aldermen, for lack of scientific training and
specific practical information, were very sceptical on
the subject--as indeed they might well be. "Mr.
Edison demonstrated personally the details and
merits of the system to them. The voltage was increased
to a higher pressure than usual, and all the
incandescent lamps at Menlo Park did their best to
win the approbation of the New York City fathers.
After Edison had finished exhibiting all the good
points of his system, he conducted his guests upstairs
in the laboratory, where a long table was
spread with the best things that one of the most
prominent New York caterers could furnish. The
laboratory witnessed high times that night, for all
were in the best of humor, and many a bottle was
drained in toasting the health of Edison and the
aldermen." This was one of the extremely rare
occasions on which Edison has addressed an audience;
but the stake was worth the effort. The representatives
of New York could with justice drink the health
of the young inventor, whose system is one of the
greatest boons the city has ever had conferred upon it.

Among other frequent visitors was Mr, Edison's
father, "one of those amiable, patriarchal characters
with a Horace Greeley beard, typical Americans of
the old school," who would sometimes come into the
laboratory with his two grandchildren, a little boy
and girl called "Dash" and "Dot." He preferred
to sit and watch his brilliant son at work "with an
expression of satisfaction on his face that indicated
a sense of happiness and content that his boy, born
in that distant, humble home in Ohio, had risen to
fame and brought such honor upon the name. It
was, indeed, a pathetic sight to see a father venerate
his son as the elder Edison did." Not less at home
was Mr. Mackenzie, the Mt. Clemens station agent,
the life of whose child Edison had saved when a train
newsboy. The old Scotchman was one of the innocent,
chartered libertines of the place, with an unlimited
stock of good jokes and stories, but seldom
of any practical use. On one occasion, however, when
everything possible and impossible under the sun was
being carbonized for lamp filaments, he allowed a
handful of his bushy red beard to be taken for the
purpose; and his laugh was the loudest when the
Edison-Mackenzie hair lamps were brought up to
incandescence--their richness in red rays being slyly
attributed to the nature of the filamentary material!
Oddly enough, a few years later, some inventor
actually took out a patent for making incandescent
lamps with carbonized hair for filaments!

Yet other visitors again haunted the place, and
with the following reminiscence of one of them, from
Mr. Edison himself, this part of the chapter must
close: "At Menlo Park one cold winter night there
came into the laboratory a strange man in a most
pitiful condition. He was nearly frozen, and he asked
if he might sit by the stove. In a few moments he
asked for the head man, and I was brought forward.
He had a head of abnormal size, with highly intellectual
features and a very small and emaciated body.
He said he was suffering very much, and asked if I
had any morphine. As I had about everything in
chemistry that could be bought, I told him I had.
He requested that I give him some, so I got the
morphine sulphate. He poured out enough to kill
two men, when I told him that we didn't keep a hotel
for suicides, and he had better cut the quantity down.
He then bared his legs and arms, and they were literally
pitted with scars, due to the use of hypodermic
syringes. He said he had taken it for years, and it
required a big dose to have any effect. I let him go
ahead. In a short while he seemed like another man
and began to tell stories, and there were about fifty
of us who sat around listening until morning. He
was a man of great intelligence and education. He
said he was a Jew, but there was no distinctive feature
to verify this assertion. He continued to stay around
until he finished every combination of morphine with
an acid that I had, probably ten ounces all told.
Then he asked if he could have strychnine. I had
an ounce of the sulphate. He took enough to kill a
horse, and asserted it had as good an effect as
morphine. When this was gone, the only thing I had
left was a chunk of crude opium, perhaps two or
three pounds. He chewed this up and disappeared.
I was greatly disappointed, because I would have
laid in another stock of morphine to keep him at the
laboratory. About a week afterward he was found
dead in a barn at Perth Amboy."

Returning to the work itself, note of which has al-
ready been made in this and preceding chapters, we
find an interesting and unique reminiscence in Mr.
Jehl's notes of the reversion to carbon as a filament
in the lamps, following an exhibition of metallic-
filament lamps given in the spring of 1879 to the men
in the syndicate advancing the funds for these
experiments: "They came to Menlo Park on a late
afternoon train from New York. It was already
dark when they were conducted into the machine-
shop, where we had several platinum lamps installed
in series. When Edison had finished explaining the
principles and details of the lamp, he asked Kruesi to
let the dynamo machine run. It was of the Gramme
type, as our first dynamo of the Edison design was
not yet finished. Edison then ordered the `juice'
to be turned on slowly. To-day I can see those lamps
rising to a cherry red, like glowbugs, and hear Mr.
Edison saying `a little more juice,' and the lamps
began to glow. `A little more' is the command
again, and then one of the lamps emits for an instant
a light like a star in the distance, after which there is
an eruption and a puff; and the machine-shop is in
total darkness. We knew instantly which lamp had
failed, and Batchelor replaced that by a good one,
having a few in reserve near by. The operation was
repeated two or three times with about the same
results, after which the party went into the library
until it was time to catch the train for New York."

Such an exhibition was decidedly discouraging,
and it was not a jubilant party that returned to New
York, but: "That night Edison remained in the
laboratory meditating upon the results that the
platinum lamp had given so far. I was engaged reading
a book near a table in the front, while Edison was
seated in a chair by a table near the organ. With
his head turned downward, and that conspicuous
lock of hair hanging loosely on one side, he looked
like Napoleon in the celebrated picture, On the Eve
of a Great Battle. Those days were heroic ones, for
he then battled against mighty odds, and the prospects
were dim and not very encouraging. In cases
of emergency Edison always possessed a keen faculty
of deciding immediately and correctly what to do;
and the decision he then arrived at was predestined
to be the turning-point that led him on to ultimate
success.... After that exhibition we had a house-
cleaning at the laboratory, and the metallic-filament
lamps were stored away, while preparations were
made for our experiments on carbon lamps."

Thus the work went on. Menlo Park has hitherto
been associated in the public thought with the
telephone, phonograph, and incandescent lamp; but it
was there, equally, that the Edison dynamo and
system of distribution were created and applied to
their specific purposes. While all this study of a
possible lamp was going on, Mr. Upton was busy
calculating the economy of the "multiple arc" system,
and making a great many tables to determine what
resistance a lamp should have for the best results,
and at what point the proposed general system would
fall off in economy when the lamps were of the lower
resistance that was then generally assumed to be
necessary. The world at that time had not the
shadow of an idea as to what the principles of a
multiple arc system should be, enabling millions of
lamps to be lighted off distributing circuits, each
lamp independent of every other; but at Menlo Park
at that remote period in the seventies Mr. Edison's
mathematician was formulating the inventor's
conception in clear, instructive figures; "and the work
then executed has held its own ever since." From
the beginning of his experiments on electric light,
Mr. Edison had a well-defined idea of producing not
only a practicable lamp, but also a SYSTEM of
commercial electric lighting. Such a scheme involved the
creation of an entirely new art, for there was nothing
on the face of the earth from which to draw assistance
or precedent, unless we except the elementary forms
of dynamos then in existence. It is true, there were
several types of machines in use for the then very
limited field of arc lighting, but they were regarded
as valueless as a part of a great comprehensive scheme
which could supply everybody with light. Such
machines were confessedly inefficient, although
representing the farthest reach of a young art. A
commission appointed at that time by the Franklin
Institute, and including Prof. Elihu Thomson,
investigated the merits of existing dynamos and
reported as to the best of them: "The Gramme machine
is the most economical as a means of converting
motive force into electricity; it utilizes in the arc
from 38 to 41 per cent. of the motive work produced,
after deduction is made for friction and the resistance
of the air." They reported also that the Brush arc
lighting machine "produces in the luminous arc useful
work equivalent to 31 per cent. of the motive
power employed, or to 38 1/2 per cent. after the friction
has been deducted." Commercial possibilities could
not exist in the face of such low economy as this, and
Mr. Edison realized that he would have to improve
the dynamo himself if he wanted a better machine.
The scientific world at that time was engaged in a
controversy regarding the external and internal resistance
of a circuit in which a generator was situated.
Discussing the subject Mr. Jehl, in his biographical
notes, says: "While this controversy raged in the
scientific papers, and criticism and confusion seemed
at its height, Edison and Upton discussed this question
very thoroughly, and Edison declared he did
not intend to build up a system of distribution in
which the external resistance would be equal to the
internal resistance. He said he was just about going
to do the opposite; he wanted a large external
resistance and a low internal one. He said he wanted
to sell the energy outside of the station and not waste
it in the dynamo and conductors, where it brought
no profits.... In these later days, when these ideas
of Edison are used as common property, and are applied
in every modern system of distribution, it is
astonishing to remember that when they were
propounded they met with most vehement antagonism
from the world at large." Edison, familiar with batteries
in telegraphy, could not bring himself to believe
that any substitute generator of electrical energy
could be efficient that used up half its own possible
output before doing an equal amount of outside

Undaunted by the dicta of contemporaneous
science, Mr. Edison attacked the dynamo problem
with his accustomed vigor and thoroughness. He
chose the drum form for his armature, and experimented
with different kinds of iron. Cores were made
of cast iron, others of forged iron; and still others of
sheets of iron of various thicknesses separated from
each other by paper or paint. These cores were then
allowed to run in an excited field, and after a given
time their temperature was measured and noted.
By such practical methods Edison found that the
thin, laminated cores of sheet iron gave the least
heat, and had the least amount of wasteful eddy
currents. His experiments and ideas on magnetism
at that period were far in advance of the time. His
work and tests regarding magnetism were repeated
later on by Hopkinson and Kapp, who then elucidated
the whole theory mathematically by means of
formulae and constants. Before this, however, Edison
had attained these results by pioneer work, founded
on his original reasoning, and utilized them in the
construction of his dynamo, thus revolutionizing the
art of building such machines.

After thorough investigation of the magnetic qualities
of different kinds of iron, Edison began to make
a study of winding the cores, first determining the
electromotive force generated per turn of wire at
various speeds in fields of different intensities. He
also considered various forms and shapes for the armature,
and by methodical and systematic research obtained
the data and best conditions upon which he
could build his generator. In the field magnets of
his dynamo he constructed the cores and yoke of
forged iron having a very large cross-section, which
was a new thing in those days. Great attention was
also paid to all the joints, which were smoothed down
so as to make a perfect magnetic contact. The Edison
dynamo, with its large masses of iron, was a vivid
contrast to the then existing types with their meagre
quantities of the ferric element. Edison also made
tests on his field magnets by slowly raising the strength
of the exciting current, so that he obtained figures
similar to those shown by a magnetic curve, and in
this way found where saturation commenced, and
where it was useless to expend more current on the
field. If he had asked Upton at the time to formulate
the results of his work in this direction, for publication,
he would have anticipated the historic work
on magnetism that was executed by the two other
investigators; Hopkinson and Kapp, later on.

The laboratory note-books of the period bear
abundant evidence of the systematic and searching
nature of these experiments and investigations, in the
hundreds of pages of notes, sketches, calculations,
and tables made at the time by Edison, Upton,
Batchelor, Jehl, and by others who from time to time
were intrusted with special experiments to elucidate
some particular point. Mr. Jehl says: "The experiments
on armature-winding were also very interesting.
Edison had a number of small wooden cores
made, at both ends of which we inserted little brass
nails, and we wound the wooden cores with twine as if
it were wire on an armature. In this way we studied
armature-winding, and had matches where each of us
had a core, while bets were made as to who would be
the first to finish properly and correctly a certain
kind of winding. Care had to be taken that the
wound core corresponded to the direction of the current,
supposing it were placed in a field and revolved.
After Edison had decided this question, Upton made
drawings and tables from which the real armatures
were wound and connected to the commutator. To
a student of to-day all this seems simple, but in those
days the art of constructing dynamos was about as
dark as air navigation is at present.... Edison also
improved the armature by dividing it and the commutator
into a far greater number of sections than
up to that time had been the practice. He was also
the first to use mica in insulating the commutator
sections from each other."

In the mean time, during the progress of the
investigations on the dynamo, word had gone out to
the world that Edison expected to invent a generator
of greater efficiency than any that existed at the
time. Again he was assailed and ridiculed by the
technical press, for had not the foremost electricians
and physicists of Europe and America worked for
years on the production of dynamos and arc lamps
as they then existed? Even though this young man
at Menlo Park had done some wonderful things for
telegraphy and telephony; even if he had recorded
and reproduced human speech, he had his limitations,
and could not upset the settled dictum of science
that the internal resistance must equal the external

Such was the trend of public opinion at the time,
but "after Mr. Kruesi had finished the first practical
dynamo, and after Mr. Upton had tested it thoroughly
and verified his figures and results several times--
for he also was surprised--Edison was able to tell
the world that he had made a generator giving an
efficiency of 90 per cent." Ninety per cent. as against
40 per cent. was a mighty hit, and the world would
not believe it. Criticism and argument were again at
their height, while Upton, as Edison's duellist, was
kept busy replying to private and public challenges
of the fact.... "The tremendous progress of the world
in the last quarter of a century, owing to the revolution
caused by the all-conquering march of `Heavy
Current Engineering,' is the outcome of Edison's work
at Menlo Park that raised the efficiency of the dynamo
from 40 per cent. to 90 per cent."

Mr. Upton sums it all up very precisely in his remarks
upon this period: "What has now been made
clear by accurate nomenclature was then very foggy
in the text-books. Mr. Edison had completely
grasped the effect of subdivision of circuits, and the
influence of wires leading to such subdivisions, when
it was most difficult to express what he knew in
technical language. I remember distinctly when Mr.
Edison gave me the problem of placing a motor in
circuit in multiple arc with a fixed resistance; and I
had to work out the problem entirely, as I could find
no prior solution. There was nothing I could find
bearing upon the counter electromotive force of the
armature, and the effect of the resistance of the
armature on the work given out by the armature.
It was a wonderful experience to have problems given
me out of the intuitions of a great mind, based on
enormous experience in practical work, and applying
to new lines of progress. One of the main impressions
left upon me after knowing Mr. Edison for many
years is the marvellous accuracy of his guesses. He
will see the general nature of a result long before it
can be reached by mathematical calculation. His
greatness was always to be clearly seen when difficulties
arose. They always made him cheerful, and
started him thinking; and very soon would come a
line of suggestions which would not end until the
difficulty was met and overcome, or found
insurmountable. I have often felt that Mr. Edison got
himself purposely into trouble by premature publications
and otherwise, so that he would have a full
incentive to get himself out of the trouble."

This chapter may well end with a statement from
Mr. Jehl, shrewd and observant, as a participator in
all the early work of the development of the Edison
lighting system: "Those who were gathered around
him in the old Menlo Park laboratory enjoyed his
confidence, and he theirs. Nor was this confidence
ever abused. He was respected with a respect which
only great men can obtain, and he never showed by
any word or act that he was their employer in a sense
that would hurt the feelings, as is often the case in
the ordinary course of business life. He conversed,
argued, and disputed with us all as if he were a colleague
on the same footing. It was his winning ways
and manners that attached us all so loyally to his
side, and made us ever ready with a boundless devotion
to execute any request or desire." Thus does
a great magnet, run through a heap of sand and
filings, exert its lines of force and attract irresistibly
to itself the iron and steel particles that are its
affinity, and having sifted them out, leaving the useless
dust behind, hold them to itself with responsive



IN writing about the old experimenting days at
Menlo Park, Mr. F. R. Upton says: "Edison's day
is twenty-four hours long, for he has always worked
whenever there was anything to do, whether day or
night, and carried a force of night workers, so that
his experiments could go on continually. If he wanted
material, he always made it a principle to have it at
once, and never hesitated to use special messengers
to get it. I remember in the early days of the electric
light he wanted a mercury pump for exhausting the
lamps. He sent me to Princeton to get it. I got
back to Metuchen late in the day, and had to carry
the pump over to the laboratory on my back that
evening, set it up, and work all night and the next
day getting results."

This characteristic principle of obtaining desired
material in the quickest and most positive way manifested
itself in the search that Edison instituted for
the best kind of bamboo for lamp filaments, immediately
after the discovery related in a preceding
chapter. It is doubtful whether, in the annals of
scientific research and experiment, there is anything
quite analogous to the story of this search and the
various expeditions that went out from the Edison
laboratory in 1880 and subsequent years, to scour
the earth for a material so apparently simple as a
homogeneous strip of bamboo, or other similar fibre.
Prolonged and exhaustive experiment, microscopic
examination, and an intimate knowledge of the
nature of wood and plant fibres, however, had led
Edison to the conclusion that bamboo or similar
fibrous filaments were more suitable than anything
else then known for commercial incandescent lamps,
and he wanted the most perfect for that purpose.
Hence, the quickest way was to search the tropics
until the proper material was found.

The first emissary chosen for this purpose was the
late William H. Moore, of Rahway, New Jersey, who
left New York in the summer of 1880, bound for
China and Japan, these being the countries pre-
eminently noted for the production of abundant
species of bamboo. On arrival in the East he quickly
left the cities behind and proceeded into the interior,
extending his search far into the more remote country
districts, collecting specimens on his way, and
devoting much time to the study of the bamboo, and
in roughly testing the relative value of its fibre in
canes of one, two, three, four, and five year growths.
Great bales of samples were sent to Edison, and after
careful tests a certain variety and growth of Japanese
bamboo was determined to be the most satisfactory
material for filaments that had been found. Mr.
Moore, who was continuing his searches in that
country, was instructed to arrange for the cultivation
and shipment of regular supplies of this particular
species. Arrangements to this end were accordingly
made with a Japanese farmer, who began to make
immediate shipments, and who subsequently displayed
so much ingenuity in fertilizing and cross-
fertilizing that the homogeneity of the product was
constantly improved. The use of this bamboo for
Edison lamp filaments was continued for many years.

Although Mr. Moore did not meet with the exciting
adventures of some subsequent explorers, he encountered
numerous difficulties and novel experiences
in his many months of travel through the hinterland
of Japan and China. The attitude toward foreigners
thirty years ago was not as friendly as it has
since become, but Edison, as usual, had made a
happy choice of messengers, as Mr. Moore's good
nature and diplomacy attested. These qualities,
together with his persistence and perseverance and
faculty of intelligent discrimination in the matter
of fibres, helped to make his mission successful, and
gave to him the honor of being the one who found
the bamboo which was adopted for use as filaments
in commercial Edison lamps.

Although Edison had satisfied himself that bamboo
furnished the most desirable material thus far
discovered for incandescent-lamp filaments, he felt
that in some part of the world there might be found
a natural product of the same general character that

Book of the day: