THE NEWEST ELECTRIC LIGHT
_Peter Cooper Hewitt and His Three Great Inventions--The Mercury Arc
Light--The New Electrical Converter--The Hewitt Interrupter_
It is indeed a great moment when an inventor comes to the announcement
of a new and epoch-making achievement. He has been working for years,
perhaps, in his laboratory, struggling along unknown, unheard of, often
poor, failing a hundred times for every achieved success, but finally,
all in a moment, surprising the secret which nature has guarded so long
and so faithfully. He has discovered a new principle that no one has
known before, he has made a wonderful new machine--and it works! What
he has done in his laboratory for himself now becomes of interest to all
the world. He has a great message to give. His patience and perseverance
through years of hard work have produced something that will make life
easier and happier for millions of people, that will open great new
avenues for human effort and human achievement, build up new fortunes;
often, indeed, change the whole course of business affairs in the world,
if not the very channels of human thought. Think what the steam-engine
has done, and the telegraph, and the sewing-machine! All this wonder
lies to-day in the brain of the inventor; to-morrow it is a part of the
world's treasure.
Such a moment came on an evening in January, 1902, when Peter Cooper
Hewitt, of New York City--then wholly unknown to the greater world--made
the announcement of an invention of such importance that Lord Kelvin,
the greatest of living electricians, afterward said that of all the
things he saw in America the work of Mr. Hewitt attracted him most.
On that evening in January, 1902, a curious crowd was gathered about
the entrance of the Engineers' Club in New York City. Over the doorway
a narrow glass tube gleamed with a strange blue-green light of such
intensity that print was easily readable across the street, and yet so
softly radiant that one could look directly at it without the sensation
of blinding discomfort which accompanies nearly all brilliant artificial
lights. The hall within, where Mr. Hewitt was making the first public
announcement of his discovery, was also illuminated by the wonderful new
tubes. The light was different from anything ever seen before, grateful
to the eyes, much like daylight, only giving the face a curious,
pale-green, unearthly appearance. The cause of this phenomenon was
soon evident; the tubes were seen to give forth all the rays except
red--orange, yellow, green, blue, violet--so that under its illumination
the room and the street without, the faces of the spectators, the
clothing of the women lost all their shades of red; indeed, changing the
very face of the world to a pale green-blue. It was a redless light. The
extraordinary appearance of this lamp and its profound significance as a
scientific discovery at once awakened a wide public interest, especially
among electricians who best understood its importance. Here was an
entirely new sort of electric light. The familiar incandescent lamp,
the invention of Thomas A. Edison, though the best of all methods of
illumination, is also the most expensive. Mr. Hewitt's lamp, though not
yet adapted to all the purposes served by the Edison lamp, on account
of its peculiar colour, produces eight times as much light with the same
amount of power. It is also practically indestructible, there being no
filament to burn out; and it requires no special wiring. By means of
this invention electricity, instead of being the most costly means
of illumination, becomes the cheapest--cheaper even than kerosene.
No further explanation than this is necessary to show the enormous
importance of this invention.
Mr. Hewitt's announcement at once awakened the interest of the entire
scientific world and made the inventor famous, and yet it was only the
forerunner of two other inventions equally important. Once discover a
master-key and it often unlocks many doors. Tracing out the principles
involved in his new lamp, Mr. Hewitt invented:
A new, cheap, and simple method of converting alternating electrical
currents into direct currents.
An electrical interrupter or valve, in many respects the most wonderful
of the three inventions.
Before entering upon an explanation of these discoveries, which,
though seemingly difficult and technical, are really simple and easily
understandable, it will be interesting to know something of Mr. Hewitt
and his methods of work and the genesis of the inventions.
Mr. Hewitt's achievements possess a peculiar interest for the people of
this country. The inventor is an American of Americans. Born to wealth,
the grandson of the famous philanthropist, Peter Cooper, the son of
Abram S. Hewitt, one of the foremost citizens and statesmen of New
York, Mr. Hewitt might have led a life of leisure and ease, but he
has preferred to win his successes in the American way, by unflagging
industry and perseverance, and has come to his new fortune also like
the American, suddenly and brilliantly. As a people we like to see a man
deserve his success! The same qualities which made Peter Cooper one
of the first of American millionaires, and Abram S. Hewitt one of the
foremost of the world's steel merchants, Mayor of New York, and one of
its most trusted citizens, have placed Mr. Peter Cooper Hewitt among the
greatest of American inventors and scientists. Indeed, Peter Cooper and
Abram S. Hewitt were both inventors; that is, they had the imaginative
inventive mind. Peter Cooper once said:
"I was always planning and contriving, and was never satisfied unless
I was doing something difficult--something that had never been done
before, if possible."
The grandfather built the first American locomotive; he was one of
the most ardent supporters of Cyrus Field in the great project of an
Atlantic cable, and he was for a score of years the president of a cable
company. His was the curious, constructive mind. As a boy he built a
washing machine to assist his overworked mother; later on he built the
first lawnmower and invented a process for rolling iron, the first used
in this country; he constructed a torpedo-boat to aid the Greeks in
their revolt against Turkish tyranny in 1824. He dreamed of utilising
the current of the East River for manufacturing power; he even
experimented with flying machines, becoming so enthusiastic in this
labour that he nearly lost the sight of an eye through an explosion
which blew the apparatus to pieces.
[Illustration: Watching a Test of the Hewitt Converter.
_Lord Kelvin in the centre._]
It will be seen, therefore, that the grandson comes naturally by his
inclinations. It was his grandfather who gave him his first chest of
tools and taught him to work with his hands, and he has always had
a fondness for contriving new machines and of working out difficult
scientific problems. Until the last few years, however, he has never
devoted his whole time to the work which best pleased him. For years he
was connected with his father's extensive business enterprise, an active
member, in fact, of the firm of Cooper, Hewitt & Co., and he has always
been prominent in the social life of New York, a member of no fewer than
eight prominent clubs. But never for a moment in his career--he is now
forty-two years old, though he looks scarcely thirty-five--has he ceased
to be interested in science and mechanics. As a student in Stevens
Institute, and later in Columbia College, he gave particular attention
to electricity, physics, chemistry, and mechanics. Later, when he went
into business, his inventive mind turned naturally to the improvement
of manufacturing methods, with the result that his name appears in the
Patent Records as the inventor of many useful devices--a vacuum pan,
a glue clarifier, a glue cutter and other glue machinery. He worked
at many sorts of trades with his own hands--machine-shop practice,
blacksmithing, steam-fitting, carpentry, jewelry work, and other
work-a-day employments. He was employed in a jeweller's shop, learning
how to make rings and to set stones; he managed a steam launch; he
was for eight years in his grandfather's glue factory, where he had
practical problems in mechanics constantly brought to his attention. And
he was able to combine all this hard practical work with a fair amount
of shooting, golfing, and automobiling.
Most of Mr. Hewitt's scientific work of recent years has been done after
business hours--the long, slow, plodding toil of the experimenter. There
is surely no royal road to success in invention, no matter how well a
man may be equipped, no matter how favourably his means are fitted
to his hands. Mr. Hewitt worked for seven years on the electrical
investigations which resulted in his three great inventions; thousands
of experiments were performed; thousands of failures paved the way for
the first glimmer of success.
His laboratory during most of these years was hidden away in the tall
tower of Madison Square Garden, overlooking Madison Square, with the
roar of Broadway and Twenty-third Street coming up from the distance.
Here he has worked, gradually expanding the scope of his experiments,
increasing his force of assistants, until he now has an office and two
workshops in Madison Square Garden and is building a more extensive
laboratory elsewhere. Replying to the remark that he was fortunate in
having the means to carry forward his experiments in his own way, he
said:
"The fact is quite the contrary. I have had to make my laboratory pay as
I went along."
Mr. Hewitt chose his problem deliberately, and he chose one of the most
difficult in all the range of electrical science, but one which, if
solved, promised the most flattering rewards.
"The essence of modern invention," he said, "is the saving of waste, the
increase of efficiency in the various mechanical appliances."
This being so, he chose the most wasteful, the least efficient of all
widely used electrical devices--the incandescent lamp. Of all the
power used in producing the glowing filament in the Edison bulb, about
ninety-seven per cent. is absolutely wasted, only three per cent.
appearing in light. This three per cent. efficiency of the incandescent
lamp compares very unfavourably, indeed, with the forty per cent.
efficiency of the gasoline engine, the twenty-two per cent. efficiency
of the marine engine, and the ninety per cent. efficiency of the dynamo.
[Illustration: The Hewitt Mercury Vapour Light.
_The circular piece just above the switch button is one form of
"boosting coil" which operates for a fraction of a second when the
current is first turned on. The tube shown here is about an inch in
diameter and several feet long. Various shapes may be used. Unless
broken, the tubes never need renewal._]
Mr. Hewitt first stated his problem very accurately. The waste of power
in the incandescent lamp is known to be due largely to the conversion
of a considerable part of the electricity used into useless heat. An
electric-lamp bulb feels hot to the hand. It was therefore necessary
to produce a _cool light_; that is, a light in which the energy was
converted wholly or largely into light rays and not into heat rays.
This, indeed, has long been one of the chief goals of ambition among
inventors. Mr. Hewitt turned his attention to the gases. Why could not
some incandescent gas be made to yield the much desired light without
heat?
This was the germ of the idea. Comparatively little was known of the
action of electricity in passing through the various gases, though the
problem involved had long been the subject of experiment, and Mr. Hewitt
found himself at once in a maze of unsolved problems and difficulties.
"I tried many different gases," he said, "and found that some of them
gave good results--nitrogen, for instance--but many of them produced too
much heat and presented other difficulties."
Finally, he took up experiments with mercury confined in a tube from
which the air had been exhausted. The mercury arc, as it is called,
had been experimented with years before, had even been used as a light,
although at the time he began his investigations Mr. Hewitt knew nothing
of these earlier investigations. He used ordinary glass vacuum tubes
with a little mercury in the bottom which he had reduced to a gas
or vapour under the influence of heat or by a strong current of
electricity. He found it a rocky experimental road; he has called
invention "systematic guessing."
"I had an equation with a large number of unknown quantities," he said.
"About the only thing known for a certainty was the amount of current
passing into the receptacle containing the gas, and its pressure. I had
to assume values for these unknown quantities in every experiment, and
you can understand what a great number of trials were necessary, using
different combinations, before obtaining results. I presume thousands of
experiments were made."
Many other investigators had been on the very edge of the discovery.
They had tried sending strong currents through a vacuum tube containing
mercury vapour, but had found it impossible to control the resistance.
One day, however, in running a current into the tube Mr. Hewitt suddenly
recognised certain flashes; a curious phenomenon. Always it is the
unexpected thing, the thing unaccounted for, that the mind of the
inventor leaps upon. For there, perhaps, is the key he is seeking. Mr.
Hewitt continued his experiments and found that the mercury vapour was
conducting. He next discovered that _when once the high resistance of
the cold mercury was overcome, a very much less powerful current found
ready passage and produced a very brilliant light: the glow of the
mercury vapour_. This, Mr. Hewitt says, was the crucial point, the
genesis of his three inventions, for all of them are applications of the
mercury arc.
Thus, in short, he invented the new lamp. By the use of what is known
to electricians as a "boosting coil," supplying for an instant a very
powerful current, the initial resistance of the cold mercury in the tube
is overcome, and then, the booster being automatically shut off,
the current ordinarily used in incandescent lighting produces an
illumination eight times as intense as the Edison bulb of the same
candle-power. The mechanism is exceedingly simple and cheap; a button
turns the light on or off; the remaining apparatus is not more complex
than that of the ordinary incandescent light. The Hewitt lamp is best
used in the form of a long horizontal tube suspended overhead in a room,
the illumination filling all the space below with a radiance much like
daylight, not glaring and sharp as with the Edison bulb. Mr. Hewitt has
a large room hung with green material and thus illuminated, giving
the visitor a very strange impression of a redless world. After a few
moments spent here a glance out of the window shows a curiously red
landscape, and red buildings, a red Madison Square, the red coming out
more prominently by contrast with the blue-green of the light.
"For many purposes," said Mr. Hewitt, "the light in its present form is
already easily adaptable. For shopwork, draughting, reading, and other
work, where the eye is called on for continued strain, the absence of
red is an advantage, for I have found light without the red much less
tiring to the eye. I use it in my own laboratories, and my men prefer it
to ordinary daylight."
In other respects, however, its colour is objectionable, and Mr.
Hewitt has experimented with a view to obtaining the red rays, thereby
producing a pure white light.
"Why not put a red globe around your lamp?" is a common question put
to the inventor. This is an apparently easy solution of the difficulty
until one is reminded that red glass does not change light waves, but
simply suppresses all the rays that are not red. Since there are no red
rays in the Hewitt lamp, the effect of the red globe would be to cut off
all the light.
But Mr. Hewitt showed me a beautiful piece of pink silk, coloured with
rhodimin, which, when thrown over the lamp, changes some of the orange
rays into red, giving a better balanced illumination, although at some
loss of brilliancy. Further experiments along this line are now in
progress, investigations both with mercury vapour and with other gases.
[Illustration: Testing a Hewitt Converter.
_The row of incandescent lights is used, together with a voltmeter and
an ammeter, to measure strength of current, resistance, and loss in
converting._]
Mr. Hewitt has found that the rays of his new lamp have a peculiar and
stimulating effect on plant growth. A series of experiments, in which
seeds of various plants were sown under exactly the same conditions, one
set being exposed to daylight and one to the mercury gaslight, showed
that the latter grew much more rapidly and luxuriantly. Without doubt,
also, these new rays will have value in the curing of certain kinds of
disease.
Further experimentation with the mercury arc led to the other two
inventions, the converter and the interrupter. And first of the
converter:
_Hewitt's Electrical Converter._--The converter is simplicity itself.
Here are two kinds of electrical currents--the alternating and the
direct. Science has found it much cheaper and easier to produce and
transmit the alternating current than the direct current. Unfortunately,
however, only the direct currents are used for such practical purposes
as driving an electric car or automobile, or running an elevator, or
operating machine tools or the presses in a printing-office, and they
are preferable for electric lighting. The power of Niagara Falls is
changed into an alternating current which can be sent at high pressure
(high voltage) over the wires for long distances, but before it can be
used it must, for some purposes, be _converted_ into a direct current.
The apparatus now in use is cumbersome, expensive, and wasteful.
Mr. Hewitt's new converter is a mere bulb of glass or of steel, which a
man can hold in his hand. The inventor found that the mercury bulb, when
connected with wires carrying an alternating current, had the curious
and wonderful property of permitting the passage of the positive half of
the alternating wave when the current has started and maintained in
that direction, and of suppressing the other half; in other words, of
changing an alternating current into a direct current. In this process
there was a loss, the same for currents of all potentials, of only
14 volts. A three-pound Hewitt converter will do the work of a
seven-hundred-pound apparatus of the old type; it will cost dollars
where the other costs hundreds; and it will save a large proportion
of the electricity wasted in the old process. By this simple device,
therefore, Mr. Hewitt has in a moment extended the entire range of
electrical development. As alternating currents can be carried longer
distances by using high pressure, and the pressure or voltage can be
changed by the use of a simple transformer and then changed into a
direct current by the converter at any convenient point along the line,
therefore more waterfalls can be utilised, more of the power of coal can
be utilised, more electricity saved after it is generated, rendering
the operating of all industries requiring power so much cheaper.
Every electric railroad, every lighting plant, every factory using
electricity, is intimately concerned in Mr. Hewitt's device, for it will
cheapen their power and thereby cheapen their products to you and to me.
_Hewitt's Electrical Interrupter._--The third invention is in some
respects the most wonderful of the three. Technically, it is called an
electric interrupter or valve. "If a long list of present-day desiderata
were drawn up," says the _Electrical World and Engineer_, "it would
perhaps contain no item of more immediate importance than an interrupter
which shall be ... inexpensive and simple of application." This is the
view of science; and therefore this device is one upon which a great
many inventors, including Mr. Marconi, have recently been working; and
Mr. Hewitt has been fortunate in producing the much-needed successful
apparatus.
The chief demand for an interrupter has come from the scores of
experimenters who are working with wireless telegraphy. In 1894 Mr.
Marconi began communicating through space without wires, and it may be
said that wireless telegraphy has ever since been the world's imminent
invention. Who has not read with profound interest the news of Mr.
Marconi's success, the gradual increases of his distances? Who has not
sympathised with his effort to perfect his devices, to produce a tuning
apparatus by means of which messages flying through space could be
kept secret? And here at last has come the invention which science most
needed to complete and vitalise Marconi's work. By means of Mr.
Hewitt's interrupter, the simplicity of which is as astonishing as its
efficiency, the whole problem has been suddenly and easily solved.
Mr. Hewitt's new interrupter may, indeed, be called the enacting clause
of wireless telegraphy. By its use the transmission of powerful and
persistent electrical waves is reduced to scientific accuracy. The
apparatus is not only cheap, light, and simple, but it is also a great
saver of electrical power.
The interrupter, also, is a simple device. As I have already shown, the
mercury vapour opposes a high resistance to the passage of electricity
until the current reaches a certain high potential, when it gives way
suddenly, allowing a current of low potential to pass through. This
property can be applied in breaking a high potential current, such as
is used in wireless telegraphy, so that the waves set up are exactly the
proper lengths, always accurate, always the same, for sending messages
through space. By the present method an ordinary arc or spark gap--that
is, a spark passing between two brass balls--is employed in sending
messages across the Atlantic. Marconi uses a spark as large as a man's
wrist, and the noise of its passage is so deafening that the operators
are compelled to wear cotton in their ears, and often they must shield
their eyes from the blinding brilliancy of the discharges. Moreover,
this open-air arc is subject to variations, to great losses of current,
the brass balls become eroded, and the accuracy of the transmission is
much impaired. All this is obviated by the cheap, simple, noiseless,
sparkless mercury bulb.
"What I have done," said Mr. Hewitt, "is to perfect a device by means
of which messages can be sent rapidly and without the loss of current
occasioned by the spark gap. In wireless telegraphy the trouble has been
that it was difficult to keep the sending and the receiving instruments
attuned. By the use of my interrupter this can be accomplished."
And the possibilities of the mercury tube--indeed, of incandescent gas
tubes in general--have by no means been exhausted. A new door has been
opened to investigators, and no one knows what science will find in the
treasure-house--perhaps new and more wonderful inventions, perhaps the
very secret of electricity itself. Mr. Hewitt is still busily engaged in
experimenting along these lines, both in the realm of abstract science
and in that of practical invention. He is too careful a scientist,
however, to speak much of the future, but those who are most familiar
with his methods of work predict that the three inventions he has
already announced are only forerunners of many other discoveries.
The chief pursuit of science and invention in this day of wonders is
the electrical conquest of the world, the introduction of the electrical
age. The electric motor is driving out the steam locomotive, the
electric light is superseding gas and kerosene, the waterfall must soon
take the place of coal. But certain great problems stand like solid
walls in the way of development, part of them problems of science, part
of mechanical efficiency. The battle of science is, indeed, not unlike
real war, charging its way over one battlement after another, until
the very citadel of final secret is captured. Mr. Hewitt with his
three inventions has led the way over some of the most serious present
barriers in the progress of technical electricity, enabling the whole
industry, in a hundred different phases of its progress, to go forward.
THE END
[Transcriber's Note:
Obvious punctuation errors have been silently repaired. The oe-ligatures
have been replaced by "oe". All words printed in small capitals have
been converted to uppercase characters.
Inconsistencies, for example in hyphenation and spelling, have been
retained.
Page 182: "Burnburg" is actually called "Bernburg".]