[Illustration: The carbon lamp--the oldest form of incandescent lamp.]
[Illustration: Standard Mazda lamp--the highest development of the
incandescent lamp.]
[Illustration: The Tantalum lamp developed just before the Mazda lamp.]
[Illustration: Improved Mazda lamp for lighting large areas--the most
efficient lamp ever made.]
The filaments of the first tungsten lamps were composed of two or
three short pieces of wire. In 1910, however, a lamp with a continuous
tungsten filament was invented which increased the strength of the lamp
wonderfully.
Mazda is a trade name given to all metal filament lamps made by the
prominent American lamp manufacturers.
The reason that the Mazda lamp is so much more efficient than the
carbon filament lamp is because the tungsten filament can be burned at
a much higher temperature than the present carbon filament, without
seriously blackening the bulb.
How Does an Arc Light Burn?
In the arc light a current of electricity is made to leap across from
the tip of one rod of carbon to the tip of another that is held a short
distance from the first. In passing across the current does not follow
a straight path, but makes a curve, or arc, whence comes the name “arc
light.”
In this form of light the carbons are not enclosed in a space from
which air is excluded, consequently there is some destruction of the
carbon. The light is due to the fact that the air between the tips of
the carbon rods opposes a high degree of resistance to the current, so
that the rods become intensely hot at their tips. The high degree of
heat causes a slow burning of the carbon at the tips, and the small
particles that burn are heated white hot before they are consumed, thus
producing light.
In order to keep the light from an arc light uniform in strength, it is
necessary to keep the tips of the carbon rods always the same distance
apart. This is practically impossible, and, as a result, the arc light
does not produce light that is well adapted for reading or for other
purposes that require constant use of the eyes. The light produced by
the arc light is very powerful, however, and for that reason it is much
used for street lighting.
What Are X-Rays?
It was discovered by Professor Conrad Roentgen in 1895, that if a
current of electricity be passed through a certain form of glass
bulb, from which most of the air has been exhausted, a disturbance
is produced in the ether that bears some resemblance to light waves.
For want of a better name to give to a disturbance which was not well
understood, Roentgen called his discovery the X-Ray, but it is now
frequently called in his honor the Roentgen ray. The nature of this
disturbance is not yet known, but as it does not affect the eye it
is not light. These rays are produced with a glass vacuum tube and a
battery from which a current of electricity is sent through the tube.
The wires of the battery are connected with two electrodes, one of
which consists of a concave disk of aluminum, and the latter of a
flat disk of platinum. The X-rays are discharged in straight lines as
shown in the figure. The most striking properties of the X-ray is its
power to penetrate many substances that are impermeable to light. All
vegetable substances, and the flesh of animals, are penetrated by it
very readily. Glass, metals, bones, and mineral substances generally
are opaque to it. Consequently, when a limb, or even the body of an
animal, is exposed to X-rays they pass through the fleshy parts,
but are stopped by the bones. Certain substances have the property
of glowing, or becoming fluorescent, when exposed to the X-ray, and
when screens of paper are coated with these substances they form a
convenient means of detecting the presence of X-rays. By holding the
hand between a tube that is giving off X-rays and a screen of this
kind, the bones of the hand will be outlined in shadow on the screen,
and the rest of the surface will glow with a greenish light. If a
bullet or other piece of metal has become imbedded in the body, it may
easily be located, if it is not in a bone, and the extent of an injury
to a bone or a joint may be plainly shown. For this reason the X-ray is
now widely used by surgeons.
How Man Learned to Fight Fire.
When you see the modern fire engine racing through the streets, gongs
ringing, with the firemen hanging on and the police clearing the track,
you should remember that it has taken man a long time to learn as much
as he has about fighting fire.
No sooner did man learn to make fire than he found it necessary to
learn how to put it out.
The first fire apparatus of record is found in Rome. The Gauls burned
the city in 390 B. C., each citizen was ordered to keep in his house a
“machine for extinguishing fire.” This consisted of a syringe.
The first record of an actual machine for putting out fire is by Hero
of Alexandria. This contrivance, a “siphon used in conflagrations,” was
used in Egypt about a hundred and fifty years before Christ.
The first record of what we would call a fire department is also found
in Rome. A disastrous fire, occurring in the reign of Augustus called
his attention to the benefit of a regular fire brigade would bring. So
he organized a fire department. It consisted of seven companies of a
thousand men each.
The first real fire engines were used in 1633 at a big fire on London
Bridge. The first fire hose was invented by the two Van der Heydes in
1672. One of the earliest engines used consisted of a tank drawn by two
horses, which threw a stream an inch in diameter to a height of eighty
feet. An improved engine was invented in 1721 by Newsham, of London,
and the first engine used in the United States was made by Newsham. The
first steam fire engine was invented by John Braithwaite, of London, in
1829.
Fire alarms came into use in medieval times. It was the custom, in many
of the towns to have a watchman stationed on a high building whose duty
it was to look for fires. As soon as he saw one, he gave warning by
blowing a horn, firing a gun, or ringing a bell.
The first London fire department consisted of ten men of each ward.
The first municipal American fire department was created in Boston in
1678. The fire engine was a hand pump bought in England.
The first leather fire hose was made in America in 1808 in
Philadelphia. Rubber hose was first made in England at about 1820.
How Did Man Learn to Cook His Food?
The primitive man lived on raw food--raw flesh, roots, fruits and nuts.
There must have been a time when he lived thus because there was a time
when he had no fires and no knowledge of how to make a fire. There are
no records, however, to show when man learned that cooked food was best.
It must have come about almost simultaneously with his knowledge of
fire, for the art of cooking goes back to the first knowledge of fire.
We do not know either how man learned to make a fire. The earliest
nations of which we have any record seem to have been acquainted with
fire and certain methods for producing it. Not only one but all early
nations seem to have been possessed of this knowledge. Occasionally
travellers have reported that people have been found who were
unacquainted with either fire or cooking, but investigation has always
proven these reports unauthentic. Cookery has always been found in
practice where people knew about fire.
It is strange how man has lost track of the beginning of his knowledge
of fire and cookery, because fire represents the beginning of man’s
culture and cookery goes hand in hand with it.
There are many legendary accounts of how man learned the value of
cooked food, all of which are based upon the accidental burning or
roasting of animals or birds. Perhaps, therefore, Charles Lamb’s “Roast
Pig” story, which we read with much laughter in our school readers, was
quite accurate from a historical standpoint. According to the story
a man’s house burned and he cried more over the fate of his pet pig
than about the loss of his house. He kept his pig in the house you will
remember and as soon as the fire died away he rushed into the debris
to look for his pet pig, hoping still to rescue him. He found him in a
corner and made haste to pick him up and carry him into the open air.
But the poor pig had been roasted to a turn and was still hot. The
man’s fingers went right into the well done roast pig and were burned.
With a cry he withdrew his fingers and put them into his mouth to blow
on them and thus he secured his first taste of roast pig, which he
found so much to his taste that he repeated the operation of licking
his fingers.
While this is but a story, it is quite likely historically correct as
to this discovery of the value of cooked food to some of the early
nations. No doubt Fire and Cookery were developed together.
When man had learned to make fire, he found that it often got beyond
his control. Here and there he would set the woods on fire quite
without intention perhaps, but with damaging results. He would watch
the conflagration and, when it was passed, he would find the baked
bodies of deer or other animals which had been overcome by the fire
and learned that baked meats were good to the taste and more easily
digestible than raw meats.
Why Does a Sponge Hold Water?
A sponge will hold water because it has, on account of the plan on
which it is grown the power of capillary attraction. The sponge is made
up of little hair like tubes. If you take a glass tube, open at both
ends and immerse one end in a vessel of water, you will find that the
water will rise in the tube to a level higher than the surface of the
water in the vessel. The smaller the hole through the glass tube, the
higher the water will rise. This is caused by the cohesion of the water
against the inside surface of the hole in the tube and causes a pull
upward. The water is pulled up into the tube because the surface of the
tube has a greater cohesive attraction for the water than for the air
which was in it and the air is forced out partly. Some liquids, such
as mercury will not rise in the same way, but is depressed in a glass
tube, since it cannot adhere to glass. Mercury however will run or rise
in a tin tube, just as water in a glass tube, because it adheres to the
tin.
Now a sponge is merely a lot of capillary tubes which have the same
power of pulling up the water as the glass tube. The tubes in a sponge
are so fine that the water will rise to the entire length of the tubes.
In addition, this adhesive quality of water to the inside of the tubes
in the sponge is so strong, that the sponge can be taken entirely out
of the water and the water will remain in it.
Why Is the Right Hand Stronger Than the Left?
The right hand is stronger than the left only in case you are
right-handed. If you have the habit of being left-handed, your left
hand becomes stronger. If you are truly ambidextrous, your strength
will be the same in both hands.
We get our strength by moving the various parts of the body, i. e., by
using them. When a little baby stretches his arms and legs and kicks,
he is only exercising naturally, making the blood circulate.
You can prove that the fact that your right hand is stronger than your
left because of the greater use or exercise you give it, by tying your
right arm close to your side and keeping it in that condition without
using it for several weeks. When you remove the bands which held it
tight, you will find your arm has lost its strength and that now your
left hand is stronger. If, however, you are left-handed and tie that
hand down for the same length of time, your right hand would be the
stronger. This shows that the strength we have in our arms and legs,
and other parts of the body, is developed by using them and giving them
rational exercise. Of course, it is possible to over-use a part of
the body, but you will notice that nature always gives us a warning by
making us tired before we come to the point where further use of that
particular part of the body would cause injury.
Why Do My Muscles Get Sore When I Play Ball In the Spring?
They do this because you have probably not been exercising the
particular muscles which you employ in throwing a ball enough in the
winter to keep you in good condition. Muscles which have been developed
through use or work need more work to keep them in condition. In a
sense certain of the muscles which you employ in playing ball have
been treated during the winter very much as if you had tied them down,
as we suggested you might do with your arm. You have not been using
them--they have not been doing enough work, and they begin to lose
their strength when for any period they have not been used enough. The
soreness that you feel is the natural condition that arises when you
begin to use a muscle that has been idle for some time.
Why Does a Barber’s Pole Have Stripes?
In early years the barber not only cut hair and shaved people, but he
was also a surgeon. He was a surgeon to the extent that he bled people.
In early times our knowledge of surgery was practically limited to
blood letting. A great many of the ailments were attributed to too much
blood in the body, and when anything got wrong with a man or woman, the
first thing they thought of was to reduce the amount of blood in the
body by taking some of it out.
The town barber was the man who did this for people and his pole
represented the sign of his business.
The round ball at the top which was generally gilded represents the
barbering end of the business. It stood for the brass basin which the
barber used to prepare lather for shaving customers.
The pole itself represents the staff which people who were having blood
taken out of their bodies held during the operation. The two spiral
ribbons, one red and one white, which are painted spirally on the pole,
represented the bandages. The white one stood for the bandage which was
put on before the blood was taken out and the red one the bandage which
was used for binding up the wound when the operation was completed.
How Was the Flag Made?
The design of our flag was outlined in a congressional resolution
passed on June 14, 1777, which stated “that the flag of the thirteen
United States be thirteen alternate stripes red and white; that the
union be thirteen stars, white in a blue field, representing the new
constellation.” After Vermont and Kentucky had been admitted to the
Union, Congress made a decree in 1794 that after May 1, 1795, “the flag
of the United States be fifteen stripes alternate red and white and
that the Union be fifteen stars white on a blue field.” This made the
stars and stripes again equal and it was the plan to add a new stripe
and a new star for each new state admitted to the Union. Very soon,
however, it was realized that the flag would be too large if we kept on
adding one stripe for each new state admitted to the Union, so on April
4, 1818, Congress passed a resolution reducing the number of stripes to
thirteen once more to represent the original colonies, and to add only
a new star to the field when a new state was admitted to the Union. At
this time there were twenty states in the Union. Since that time none
of the flags of the United States have more than thirteen stripes while
a new star has been added for each state until now we have forty-eight
stars, representing the forty-eight states.
Why Are Some Guns Called Gatling Guns?
A gatling gun is a kind of gun invented by Richard Jordan Gatling
in 1861 and 1862 and so it receives its name from its inventor. The
original gatling gun had ten parallel barrels and was capable of firing
1,000 shots per minute when operated by hand power. It was discharged
by turning a crank and would shoot in proportion to the rapidity with
which the crank was turned. It was at first not a huge success but has
from time to time been improved so that the crank is now turned by
electric power and about fifteen hundred shots per minute can be fired
with it.
How Did Hobson’s Choice Originate?
As used today, this expression means a choice with only one thing to
choose. Tobias Hobson was a livery stable keeper at Cambridge, England,
during the reign of King Charles I. He kept a stable of forty horses
which he hired out by the hour or day, and was famous in his day so far
as a livery stable keeper could be.
When you went to Hobson to hire a horse, you had the privilege of
looking over all the horses in the stable to decide which one you would
like to drive, but he always made you take the one in the stall nearest
the door. In this way all the horses in the stable were worked in turn
and while you might pretend to choose your own horse, you really had no
choice--you had to take the one nearest the door or none. As soon as a
horse was hired, the other horses in the stable were moved up, each one
to the stall next towards the door so there was always a horse in the
stall nearest the door.
Why Do They Call It a Honeymoon?
The word Honeymoon which is commonly used to describe the first
few weeks after marriage, has always meant the first month or moon
after marriage, but does not have any reference to the month or moon
excepting as that describes a certain period of time.
The word originated in an old custom quite common among newly married
couples among the ancient Teutons of drinking a kind of wine made from
honey during the first thirty days after being married.
In these days newly married couples generally take a trip away from
home for a short or longer period after their wedding day and this is
called the honeymoon whether it is but a few days or three months or
more. The custom of drinking wine made from honey has been abandoned so
that the word is now used in an entirely different sense than formerly.
Why Is a Horseshoe Said to Bring Good Luck?
The luck of the horseshoe comes from three lucky things always
connected with horseshoes. These consist of the following facts: It is
the shape of a crescent; it is a portion of a horse; it is made of iron.
Each of these has from time immemorial been considered lucky. Anything
in the shape of a crescent was always considered a thing to bring luck.
From the earliest times, too, at least since the world knew something
of the qualities of iron, iron has been regarded as a thing to give
protection and incidentally that would involve good luck. And lastly
the horse, since the days of English mythology, has been regarded as
a luck animal. When, then, we had a combination of the three--the
crescent, the iron and the horse in one object, it became a true lucky
sign in the eyes of the people.
Some Wonders of the Human Body.
There are said to be more than two million little openings in the skins
of our bodies to serve as outlets for an equal number of sweat glands.
The body contains more than two hundred bones. It is said that as much
blood as is in the entire body passes through the heart every minute,
i.e., all the blood in the body goes in and out of the heart once every
minute. The lung capacity of the average person is about 325 cubic
inches.
With every breath you inhale about two-thirds of a pint of fresh air
and exhale an equal amount if you breathe normally.
The stomach of the average adult person has a capacity of about five
pints and manufactures about nine pounds of gastric juice daily.
There are over five hundred muscles in the body all of which should be
exercised daily to keep you in the best condition. The average adult
human heart weighs from eight to twelve ounces and it beats about
100,000 times every twenty-four hours. The perspiration system in the
body has only very small ducts or pipes, but there are about nine miles
of them. The average person takes about one ton of food and drink each
year. We breathe about eighteen times a minute, which amounts to about
3,000 cubic feet an hour.
Where Did the Expression “Kick the Bucket” Originate?
The expression originally came from the method used in stringing a
hog after killing it. The pig after being slaughtered was hung by the
hind legs. A piece of bent wood was passed in behind the tendons of
each of the hind legs and the pig hung up by this stick of wood much
like we hang up clothes with a clothes hanger today. The piece of wood
was called a bucket. The “bucket” part of the expression does not,
therefore, refer to a bucket at all but to this bent piece of wood. All
are not agreed on this explanation, however, as it does not explain
where the “kick” comes in. Many investigators hold to the belief that
a man named Bolsover was the first to “kick the bucket” literally and
that the expression came from the manner of his death. He stood on a
pail or bucket while arranging to hang himself by tying a rope around
his neck and to a beam which he could not reach without standing on the
bucket. When ready he kicked the bucket out from under his feet and
so succeeded in carrying out his own wishes and in so doing coined a
famous expression which still means “to die.”
How Did the Word “News” Originate?
The word “News” which was created to describe what newspapers are
supposed to print, came from the four letters which have for ages
been used as abbreviations of the directions of the compass. In this
N stands for North, E for East, S for South and W for West, and in
illustrating the points of the compass the following diagram has long
been used:
N
|
W--+--E
|
S
The earliest newspapers always printed this sign on the front pages of
their papers in every issue. This was done to indicate that the paper
printed all the happenings from four quarters of the globe.
Later on some enterprising newspaper man who may have forgotten the
original significance of the letter in the diagram, arranged the
letters N. E. W. S. in a straight line at the head of the paper and
that is how what we read in the papers came to be known as news.
Almost one-half the whole number of newspapers published in the world
are published in the United States and Canada.
Who Made the First Umbrella?
No one knows who made the first umbrella but we know that Jonas Hanway
of London was the first man to carry one over his head to keep off the
rain.
Umbrellas seem to have been known as far back as the days of Ninevah
and Persepolis, for representations of them appear frequently in the
sculptures of those early days. The women of ancient Rome and Greece
carried them but the men never did.
Mr. Hanway is said to be the first man who walked in the streets of
London with an open umbrella over his head to keep off the rain. He is
said to have used it for thirty years before they came into general use
for this purpose.
[Illustration: HOW MAN LEARNED TO TELL TIME
The first picture shows what was probably man’s first method of telling
time. The principle was the same as that of the sun-dial. It provides
to-day an accurate method of telling time.
Of course, man in the early days needed to find some other means of
noting the passing of time at night, for then the sun cast no shadow
for him. His ingenuity taught him to make a candle which was light and
dark in alternate rings, and as each section burned he made a mark to
record the passing of a certain length of time. Before candles were
invented he used a rope in which he tied knots at equal spaces apart
and which he burned as shown in the third picture.]