MORE MARVELS OF SCIENCE
COLOUR PHOTOGRAPHY, THE TUNGSTEN ELECTRIC LAMP, THE PULMOTOR,
AND OTHER NEW INVENTIONS INVESTIGATED BY OUR BOY FRIEND
Before we leave our good friend the scientist and his young
companion, let us go over a few more of the things about which
they talked. To take up all of them would be to prolong this book
indefinitely, for the boy's mind was ever unfolding to the new things
of the world and with each subject mastered, or at least partially
understood, he was anxious to go on to the next. Not that he did not
have his special hobbies upon which he spent most of his time, for he
did, but that did not prevent his inquiring young mind from reaching
out for new and more wonderful things once he had come to realize the
world of marvels in which we live.
One of this youth's favourite pastimes was photography, and as an
amateur his work had attracted considerable attention from his
friends. One day in the summer, when all the trees, shrubs, and
flowers were at the height of their beauty, he came into the
laboratory where his scientific friend was working over an experiment.
"I have heard of a process of colour photography," he said, "and I
wonder if I couldn't make use of it to get some good pictures out in
the country, showing just exactly how it is."
"Certainly," replied his friend. "There are a number of systems of
colour photography now--all invented within the last few years.
None of them is perfect though, and you would have the added fun of
carrying on some experiments that might bring to light some valuable
knowledge.
"While it is possible to make coloured photographic prints now,
by means of a specially treated paper, colour photography is best
known as a means of making beautiful transparent glass plates and
lantern slides. When held up to the light, the transparencies give
an accurate picture of the scene in natural colours. The paper I
mention can be bought at the photographic houses, but the inventors
do not claim yet that their process is so perfect as to give exact
reproductions of all the shades of colours unless they are well
defined in the positive plates. The prints are made from the positive
transparencies in just the same way that photographic prints are made
from black and white photographic plates."
"Let's try some colour photographs," promptly said the boy. "Will you
go out into the country with me some Saturday and help me?"
"I certainly will be glad to go with you, but you are a better
photographer than I am, for you see, about the only kind of
photography I do now is with a microscope, such as you have looked
through here many times. Your own regular camera and tripod will be
all you will need, for I will buy the colour plates upon which the
pictures are to be taken."
They made their trip to the country on the first pleasant Saturday,
and while they were out the scientist explained many points about the
system.
"Years ago," he said, "even before that wonderful Frenchman,
Daguerre, invented light photography, scientists were trying to
discover some means of mechanically registering on paper, the
beautiful things they saw in nature, in their natural colours, as
well as in their natural form in black and white. All through the
years of the development of photography with light and shadow,
scientists never relaxed their search for some way of photographing
colours. Although many of them hit upon the colour screen idea by
which it finally was accomplished, there remained years and years
of patient experiment. Prof. James Clark Maxwell, Ducos du Hauron,
Doctor Konig, Sanger Shepherd, and, in later years, Frederick Eugene
Ives, of Philadelphia, all worked on the idea.
"In 1907, however, Antoine Lumiére, of the famous French photographic
house that bears his name, announced a system of colour photography
which has grown in popularity ever since. The system, which is known
as the autochrome, was the result of many years patient study and
research with his sons who are associated in business with him."
The scientist then went on to explain that in attacking the problem
the investigators first had to learn all they could about colours,
and how they are reflected by light rays. As we have seen in the
colour process for motion pictures there are really only three
fundamental or primary colours, and all other shades and tints are
made up from combinations of these. The three are blue-violet, green,
and orange-red, and a screen of these forms the foundation of all the
colour plates now used.
In the autochrome process the lowly potato, which we generally
think of merely as a common article of our food, forms the first
factor. The starch of the potato is ground down and sifted so that
the grains are the same size--not more than 0.0004 to 0.0005 of an
inch in diameter. These grains then are divided into three equal
portions, and each portion is dyed, respectively, blue-violet, green,
and orange-red. The three little piles of starch grains are then
mixed together in suitable amounts and dusted on to a plate, which
has previously been coated with a substance to make them stick. The
difficulty in dusting on the starch grains is great, for they must
cover the whole plate equally and yet not make any piles of starch
at any one point, for to have several grains on top of one another
would spoil the effect. The extreme delicacy of this operation will
be appreciated when it is realized that there are over five million
grains to the square inch. When the starch is all properly placed it
makes the colour screen, though in appearance the plate is a dark
gray.
The plate is next put through a rolling process so that all the
grains are flattened out to form a mosaic covering over the whole
surface. In spite of all the manufacturers can do there will still be
some microscopic spaces between the particles, and these are filled
up with a fine powder of carbon to prevent the passage of light.
The screen is then coated with a very thin layer of varnish and upon
this is laid a thin and extremely sensitive photographic emulsion.
"And so that is the way these autochrome plates we have here were
made," concluded the scientist. "Now our troubles begin, for we must
be careful to give them a fair trial with the proper kind of an
exposure and the proper kind of development."
As the plates are extremely sensitive to all kinds of light the
scientist cautioned the boy against loading the camera carelessly. It
is better, he said, to load in a dark room.
In putting the plates in the camera the plates are reversed and
instead of placing the sensitized side toward the lens, the uncoated
glass is put in front and the photograph is taken through the glass.
Thus, the image first passes through the glass, next, through the
grains of coloured starch, and, lastly, is recorded on the sensitive
photographic emulsion.
Before loading the camera, however, the scientist fitted a yellow
colour screen over the lens, explaining that this was necessary to
absorb some of the overactive blue-violet light rays, to which the
emulsion is extremely sensitive.
In exposing the plate what happens is this: Suppose a green field
is to be photographed. The green rays of light, reflected from
the field, pass through the lens, and through the glass support
of the plate. But when they reach the coloured starch, the green
rays pass through the green particles of starch, but not through
the violet-blue particles, or the orange-red particles, for the
grains of other colours absorb the green rays and hold them. Thus,
development would show that the green light rays passing through the
green starch particles caused the emulsion to darken under the green
particles in just the proportion in which the green light reached
them, and to record the image they carried. As the light would not
pass through the other coloured particles they would not record any
image. Thus a negative is produced, as we have seen, not the colour
we see in life but the complement. By treating the plate with a
solvent of silver the tiny black specks that were brought out behind
each green particle are removed and each starch grain is allowed to
transmit exactly the colour we see in life. In other words, we have
a positive.
This is just as true of all the shades and hues as it is of the three
fundamental colours, for the various rays of light will penetrate the
starch in just the proportion of the hues they represent in the scene
before our eyes. While the silver solvent will remove the dark images
built up by the penetration of green light, it will leave behind the
particles of red-orange, and blue-violet, backed up by the creamy
silver bromide of the emulsion. If above the green field we had a
blue sky, the blue-violet particles would let the blue-violet rays
penetrate them, and record the image of the sky.
After the negative has been treated and made a positive, a second
development reduces the silver bromide to opaque metallic silver,
preventing any light from passing through the grains through which a
part of the image did not pass. This second bath also brightens the
colours, while the hypo bath removes the unaltered silver bromide
ensuring permanency to the image.
"Of course in taking these colour photographs," went on the
scientist, "we must take into consideration a great many things, to
which the manufacturers will call your attention in their booklets.
The exposure is the most important part of all, for these plates are
necessarily slow and must be exposed for a much longer time than the
ordinary rapid plates. For instance, this field, with this bright
summer sunlight, will require a full second with this lens at U. S.
4."
The scientist then went on to give the boy directions for developing
his colour plates, as follows:
The whole process of development consists of three operations and but
two solutions are required, one of them being kept preferably in two
stock solutions. Apothecary weight is used.
STOCK DEVELOPER
Water 30 ounces
Metoquinone 3-1/2 drams
Sodium sulphite (dry) 3 ounces
Ammonia (density 0.923 or 22 degrees B) 1 ounce
Potassium bromide 1-1/2 drams
Dissolve the metoquinone first in lukewarm water and then the other
chemicals in the order given.
STOCK REVERSING SOLUTIONS
A. Water 25 ounces
Potassium permanganate 50 grains
B. Water 25 ounces
Sulphuric acid 4 drams
Errors in exposure are to be corrected by varying the duration
of development and the amount of stock solution added after the
appearance of the image. Use the solutions at a temperature of 60
degrees Fahrenheit, and start development of a 5 × 7 plate in
Water 4 ounces
Metoquinone stock solution 2 drams
Have ready two graduates, one containing 6 drams of the stock
developer, the other 2-1/4 ounces. Begin counting seconds upon
immersion of the plate in the weak developer and watch for the
outlines of the image, not considering the sky. If the time of
appearance is less than 40 seconds, add the smaller quantity of stock
solution; if more, add the greater. The total times of development
are given in the following table. Cover the tray for protection from
light as soon as the solution has been modified properly.
==================+==================+=======================
TIME, IN SECONDS, | QUANTITY OF | TOTAL DURATION OF
OF APPEARANCE | METOQUINONE | DEVELOPMENT, INCLUDING
OF IMAGE, | STOCK SOLUTION | TIME OF APPEARANCE.
DISREGARDING |TO BE ADDED AFTER |---------+-------------
THE SKY. | IMAGE APPEARS. | Minutes.| Seconds.
------------------+------------------+---------+-------------
12 to 14 | 6 drams | 1 | 15
15 " 17 | " | 1 | 45
18 " 21 | " | 2 | 15
22 " 27 | " | 3 | 15
28 " 33 | " | 3 | 30
34 " 39 | " | 4 | 30
-------- | ------------ | -- | ---
40 to 47 | 2-1/2 ounces | 3 |
Over 47 | " " | 4 |
------------------+------------------+---------+-------------
As soon as development is finished rinse the plate briefly, immerse
in equal parts of the reversing solutions and carry the tray into
bright daylight. Gradually the image clears and the true colours are
seen by transmitted light. In three or four minutes the action will
be complete. Rinse the plate in running water for thirty or forty
seconds and immerse again, still in daylight, in the developer. In
three or four minutes the white parts of the image will be seen to
have turned entirely black. The plate may now be rinsed for three or
four minutes in running water and set away to dry without fixing.
To avoid frilling in summer, it is well to immerse the plate for two
minutes after reversal in
Water 5 ounces
Chrome alum 25 grains
After a brief rinsing proceed with the second development as usual.
The completed transparency may be protected from scratches to a
certain extent by varnishing the film side, although this is not
necessary. The varnish consists of
Benzole (crystallizable) 5 ounces
Gum dammar 1 ounce
It should be applied cold in the usual way, making sure that the
entire surface is covered, and then setting the plate on edge to dry.
The other colour processes now used with success also are based upon
the colour screen.
The process known as the omnicolore, which was brought out in France,
depends upon a screen consisting of a very fine network of violet
lines in one direction, crossed by red and green lines at right
angles. The usual sensitive emulsion is placed over these. The lines
run more than two hundred to the inch but they can be seen by close
examination of the plate.
In the Thames process which was brought out in England the colour
screen and the sensitive emulsion are on separate plates which must
be bound together during exposure and again placed in register or in
exactly the same relative position after development. This causes
some trouble, but reduces expense as the failures waste the sensitive
plates but not the colour screens. The primary colours instead of
being scattered at random, as in the autochrome system, are arranged
in a pattern to give the proper proportions to each. The red-orange
and green particles are arranged in circles, with the green a little
larger than the red ones, while the blue particles fill the spaces.
THE NEWEST ELECTRIC LIGHTS
One evening our boy friend entered the scientist's laboratory and
found it more brilliantly illuminated than it ever had been before.
"Oh, I know," he said looking up at the ceiling, "those new electric
lights up there are tungsten lamps. It certainly makes a difference
in the looks of this place."
"Lights up all the dingy corners, doesn't it?" answered his friend.
"You remember," he continued, "we talked last week about some of the
new kinds of electric light and that made me think that I might just
as well take advantage of what other scientists have done and install
this newest kind of electric lamps."
From the ceiling were suspended several stationary fixtures with
bright glass reflectors. The lamps the boy saw were somewhat larger
than the usual electric light bulbs, and gave off a beautiful white
light instead of the slightly yellowish illumination that comes
from the ordinary ones. He saw that the filament from which the
illumination came was not arranged in a series of horseshoe curves,
as in the case of the ordinary globes, but that it was strung
between the ends of cross trees, or "spiders," so that there was a
greater total length of filament in the same size bulb than in the
ones used before the invention of the tungsten lamp. It is a sight
familiar enough to most boys in these days of the rapid adoption of
new inventions, but it brought to the boy's mind a question that had
often occurred to him before.
"Who invented tungsten lights?" he asked.
"Well, it would hardly be right to say that any one individual
invented them, for they were really a development of science worked
out by many men, who studied the problem for many years. This caused
a number of very bitter lawsuits over the patents and brought about
the imprisonment of one United States patent office official who was
convicted of falsifying the records at Washington to help one of
the inventors. This inventor was John Allen Heany, and his patents
were rejected finally, the rights of the tungsten filament going to
the General Electric Company. The name 'tungsten' is taken from the
material of which filament, or the little wire which lights up in the
globe, is made."
"What is tungsten?" asked the boy.
"Tungsten is a metal that for a great many years some of our most
prominent chemists and scientific investigators declared could not be
put to the use we see it here," answered the man.
Noticing that the boy leaned forward in his chair, keen on his every
word, the boy's friend continued his description of this strange
metal that has been put to work lighting us in our march along the
road of life.
He explained that tungsten, or wolfram, was discovered in 1781 and
was named from the Swedish words "tung" (heavy) and "sten" (stone).
The mineral is not found in a pure state but rather in wolframite,
which is what the scientists call a tungstate of iron and manganese,
and also in schoolite which is calcium tungstate. Pure tungsten is
bright steel gray, very hard, and very heavy. It is one of the most
brittle of all the metals and for that reason was put to very few
uses before the invention of the tungsten lamp. It was most commonly
used, however, in various steel processes, to harden the metal.
From the time Edison invented the incandescent lamp in 1879, right up
to the present electricians have tried to get a better electric light
filament. A number of persons conceived the idea of making a filament
of tungsten on account of its peculiar characteristics, which seemed
to be just about the ones needed for the ideal electric light globe.
In its fundamental idea the tungsten lamp is not very greatly
different from the early Edison incandescent lamps, but in
the application of the principle there is half a century of
accomplishment packed into a little over a quarter of a century of
years. Edison saw that he must have a filament that would carry the
current of electricity, but yet one which would be of such high
resistance that it would not take up all the current fed to it. He
saw that he had to have a filament that would heat to incandescence
with the electrical current, and yet one that would stand a certain
amount of wear and tear, and which would not be consumed by the heat.
To obtain the latter effect he put his filament in an air-tight
glass globe from which the atmosphere was exhausted, leaving it in
a vacuum. As there was no air, there was no oxygen, and hence there
could be no oxidization, or, in other words, combustion of the
filament.
Edison thought that success lay in a carbon filament, and in these
early days when he was experimenting at his Menlo Park laboratory he
carbonized just about everything he could lay his hands on and tried
heating the result to incandescence in the vacuum globe. Finally,
on October 21, he carbonized a piece of cotton thread and put it
in his vacuum globe in the form of a horseshoe loop. On connecting
it with his electric circuit he was rewarded by seeing a brilliant
incandescent light that lasted without dimming for forty straight
hours.
What a dim, dingy little light it was in comparison to the world
famous lights that Edison now puts forth! And yet in one way it
was the most brilliant light that ever had shone in the world, for
it showed mankind the pathway toward a complete system of electric
lighting by incandescent lamps.
The carbonized cotton thread filament had many drawbacks, and Edison
continued carbonizing various fabrics and fibres, including, it is
said, some of the red hairs out of the beard of one of his loyal
staff! At last he hit upon a filament made of carbonized Japanese
bamboo that was very successful for a number of years, but this was
later superseded by a cellulose mixture mechanically pressed out by
dies.
Meanwhile, several investigators began work with tungsten and a
similar metal called tantalum because of their extremely high
melting points, high resistance, and other technical characteristics
favourable for an incandescent filament.
For years they had no success because the metal was so very brittle
that they could do nothing with it, but finally a filament of
pressed tungsten was brought out. In this type of lamp several
filament loops would be fused or welded together to make one complete
filament. The result was a very fine light, but the little wire was
too fragile to stand hard usage, and owing to the fact that the
various connected loops were not all of exactly the same thickness,
one frequently burned out far ahead of the others and caused early
lamp failure.
The next step, and the one which a great many scientists had declared
impossible, was the manufacture of a tungsten wire through a regular
process of drawing it out through dies to the desired length, and in
the desired thickness. The investigators had declared that in spite
of all they could do, tungsten was too brittle ever to be drawn into
wire. In the latest methods this is accomplished with such perfection
that tungsten wire of 0.0015 of an inch in diameter is produced.
"With the invention of a method for drawing out tungsten wire,"
continued the scientist, "an almost ideal lamp was practically
accomplished. The wire simply was strung on the spiders or cross
pieces, and a filament of almost any length giving almost any desired
candlepower light could be used.
"You see in an incandescent light the higher the melting point of
the filament the greater the quantity of light for the amount of
electricity used. Also tungsten has a low vapour tension, which
prevents discolouration of the globe by the evaporation of the
filament. It also has other advantages which are too technical for us
to go into.
"Of course, tungsten lamps still have the drawback of being rather
delicate. When not in use, and when the filament is cold, it is apt
to break with rough treatment, but when lighted the filament, being
at a white heat, is more durable. This delicacy of the tungsten lamp
is the reason the fixtures for most of them are placed in stationary
positions, rather than on swinging drop cords, as is the case with so
many carbon incandescent lights.
"While the tungsten lamp is far from perfect, it is a great advance
over other forms, and an advance in the right direction, for it gives
a better light with a smaller consumption of electricity than other
types. I think your father will agree with me that anything that will
help ever so little to reduce the high cost of living is a benefit."
"But," answered the boy, "there are other new kinds of electric
lights besides tungsten, aren't there?"
"Oh, of course, but they are hardly as generally used as the tungsten
light. There is the mercury light about which you read in 'The
Second Boys' Book of Inventions,' several new kinds of arc lights,
the Nernst light, the tantalum lamp (which we know is much like the
tungsten lamp with the exception that in the latter each loop of the
wire can be made longer), and the new carbon dioxide gas electric
light, which is a very good imitation of daylight.
"From all our little scientific journeys you have doubtless formed
the idea that light is not the simple thing it seems, and that the
rays of different kinds of light will bear a limitless amount of
study. Now some of the greatest scientists the world ever has known
have spent the best part of their lives trying to produce a light
that would duplicate the beautiful health-giving rays of the sun.
This light we are speaking of comes as near to it as any."
He picked up a long glass test tube and holding it between his
fingers said: "Now if this tube were exhausted of air to a vacuum,
and we had an ingenious little device at each end which would allow
just the right amount--no more, no less--of carbon dioxide gas to
enter it, and also we had electrodes at either end, and connected
them to an alternating current, we would have a rough model of the
light that duplicates daylight.
"In actual practice the vacuum tubes are long, and turn upon
themselves in many lengths. You have seen these lights in many
places, for photographers, lithographers, dye works, textile mills,
and all other places where the true light of day is necessary for the
judgment of colours are adopting them for their night work."
"But the light is a ghastly pale blue," interrupted the boy. "It
doesn't look like daylight to me."
"No, you are thinking of the mercury light, which also is strung
around in tubes. That has a blue-greenish tinge to it, and gives
people's faces a disagreeable greenish tinge, but this carbon dioxide
electric light is white with a salmon pink tinge. Of course it isn't
perfect, but the men who developed it from the work of others who
started on this idea years ago, are constantly at work trying to
improve it."
THE PULMOTOR
"My father read in the paper to-day about a new machine called the
pulmotor, which he said was one of the greatest inventions ever
brought out," said our boy friend one day in the winter of 1911-12.
"Yes, it is a great invention," replied the scientist, "and like so
many other big things it is so simple we wonder how it is no one was
bright enough to think of it before. I suppose most of us are too
busy trying to make money."
"My father said it would be a fine thing for humanity and that it
would save hundreds of lives every year."
"That is true, and the pulmotor is just about the newest invention
of our time, along those lines. When I first heard of it, I wrote to
a friend of mine in Chicago, where it was brought out, and asked him
about it."
"How does it work?" asked the boy, and ever willing to explain the
marvels of science to his young friend, the scientist took a pencil
and a piece of paper to illustrate as he talked.
As every boy knows, oxygen is the property in the air we breathe that
gives us life. Also, every boy knows that physicians and surgeons
use pure oxygen stored in iron tanks to restore respiration to the
lungs of their patients when breathing has almost stopped. Until
the invention of the pulmotor, how ever, this oxygen was simply
introduced into the patient's lungs by placing the tube in his mouth
and turning on the valve.
The pulmotor _makes_ the patient breathe--because it carries on the
function for him artificially. "In Chicago this winter," said the
boy's friend, "there were several cases where the pulmotor brought
back to life people who apparently were dead, from asphyxiation, or
gas poisoning. The machine is most successful where breathing has
stopped through some unnatural interference, and the rest of the
organs are physically intact, but of course it can be used in all
surgical cases just as the ordinary oxygen tank is used.
"One case, and probably the one about which your father was reading,"
continued the boy's friend, "was that of a family of three, father,
mother and little girl, who were asphyxiated, and were apparently
dead. The pulmotor pumped pure oxygen into their lungs until they
began to breathe naturally again."
When the pulmotor is unpacked from its little wooden box, about the
size of a suitcase, it looks like a confusion of rubber tubes and
bags. The oxygen is contained in the tank under high pressure, and
this pressure also furnishes the power to keep up the artificial
breathing.
[Illustration: THE PULMOTOR
A--Oxygen tank. B--Reducing valve. C--Inspirator.
D-E--Inlet and outlet of controlling valve. F--Operating bellows.
G--Dashpot bellows. H--Face cap.]
The oxygen flows from the tank through a reducing valve, which cuts
down the pressure, and into a controlling valve whence it flows by
a rubber tube to the face cap which fits tightly over the patient's
nose and mouth. The patient's tongue is kept from sliding back into
his throat by a pair of forceps placed for the purpose.
Thus, the oxygen is forced into the lungs by the pressure, but
when it reaches a certain degree, about what it would be in normal
breathing, a bellows connected with the controlling valve is pressed,
and the pressure is turned to suction so that the oxygen that has
been forced into the lungs is brought out, through the outlet,
causing the poisonous gases to be expelled from the lungs. After the
exhalation is complete the controlling valve works again and another
blast of pure oxygen is sent into the lungs, only to be withdrawn at
the proper moment. This is kept up until the patient's breathing is
normal.
We will leave the scientist and his young friend here, for already we
have spent more time in following their journeys and talks than we
set out to do. We have not touched upon every invention of the last
ten years or so, nor every important development, by a long ways, but
we have gone far enough to get a pretty fair idea as to the trend of
modern thought in inventive research.
This is the epoch of electricity, and of the utilization of all the
great forces of Nature that have been right here to our hands since
the world began, but which it has taken all these thousands of years
to discover and analyze. More and more man is coming to see that
Nature's own forces will carry on the big works of the world, if they
are properly led through an understanding of their laws. We have
aviation because man learned how to utilize the fact that air gives
support; we have wireless telegraphy, and we will have the wireless
transmission of power, because man learned that Nature has her own
perfect system of carrying electrical currents when they are properly
delivered to her, without any cumbersome system of wires; we have the
Tesla turbine because its inventor found out that Nature gave steam,
gas, water, and even air, certain properties that are intangible, and
yet stronger far than mere brute force; and so it goes:
Ever a greater familiarity with Nature leads to greater progress, and
a happier, more interesting world.
THE END
Transcriber's note:
Minor spelling inconsistencies, mainly hyphenated words, have been
harmonized. Obvious typos have been corrected. A "List of Diagrams"
section has been added as an aid for the reader. The tables in
Chapter II have been split in order to meet width of line
requirements. The first column has been duplicated in the second
half of each table.
End of Project Gutenberg's The Boy's Book of New Inventions, by Harry E. Maule