electronic rocket, but when a cathode ray tube gets that big it really
needs a new name. The idea is the same as that of a rocket. You know
the experiments the Germans, the millionaire Opel, and others carried
out in 1927 with rocket automobiles? They had a terrible time with
their rockets because the heat of one set off the next. The result was
a disastrous explosion--and they had a whole ocean of air to cool them!
What would a rocket do in free space? Also remember the principle of a
rocket is that you shoot particles out of the rear at a very high speed
and thus impart the kick to the ship. The electronic rocket does the
same thing--but instead of shooting molecules of hot gas, it shoots
electrons, a giant cathode ray tube such as Coolidge had in 1927, but
his was so small that the kick was immeasurable. Remember that as the
velocity of the electrons approaches that of light, the mass increases
and so the electrons as shot from a cathode ray rocket may weigh as
much as a milligram. The problem of propulsion then is not hard with
atomic energy to supply the terrific voltages needed to run the tube.
But the cathode rays are going to be their first weapon. Cathode rays
are absorbed by any object they hit, and their terrific energy is
converted to heat. They are deadly in themselves, and the heat is of
course deadly. They will also have heat rays. I can make a heat ray
with atomic energy, though mine is derived from material. The only way
we can fight them is to know beforehand what we are to meet. This is to
be a war for a world, and the war will be a battle of titanic forces.
The weaker of the forces will be a million times greater than anything
man has ever known before, and either of these two forces would, if
fully applied, blast our planet from its place around the sun! Such
forces can not be withstood. They must be annulled, deflected, or
annihilated by some greater force. Only when we know what to expect can
we fight them, and live. Remember, if they once succeeded in getting
one weak spot in our armor, we can never have another chance, and the
world can never hope to fight them--mere armies and a navy or two, with
a couple of air forces thrown in--what would they amount to? The energy
of atoms could destroy them like paper in a blow-torch--think what
would happen to one of those beautifully absorbing grey battleships
if a heat ray touched it! Their eighteen-inch steel armor would not
melt--it would boil away! A submarine would be no safer--they could
explode the water about it into steam and crush it. The effect of a
heat ray in water is just that--the water is converted to steam so
suddenly that there is a terrific explosion. The cathode rays could
sweep an army out of existence as hose might wash away an army of mud
soldiers. They won't have gases. They will have no use for them. They
could wipe a city off the map, leave only a great crater in the scarred
Earth, while men were getting ready to lay a gas barrage. A shell would
certainly just bounce off of the armor of my ship and I suspect that
it would do the same with the Martian ships. Earth has only one weapon
that can even bother them! And that one weapon is the one factor they
did not figure on! It is the 'Terrestrian.' But now, if we want to make
that one factor upset the whole equation, we have to calculate how to
make its value a maximum, and to do that we have to know every other
factor in the equation. I have suggested two weapons they will have,
the cathode rays and the heat ray. They will, of course, have others;
they will have atomic bombs, and I am sure that they will find us so
dangerous that they will be willing to lose a ship and crash us. This
gives us something else to avoid. Can any of you think of something
else?"
"Good Lord Steve, haven't you thought of enough?"
"Plenty, Dave, but it isn't considered good form in military
proceedings to permit the enemy to surprise you. In fact, it is highly
probable that if he does, you will get a new form, one more adapted to
aerial transit."
"Yes, that's true, too. But I remember reading once that ultra-violet
light was invisible, and very dangerous to the body. I wonder if they
will use that?"
"They may, but I greatly doubt it. Air is very nearly opaque to
ultra-violet light, above a certain limit, and below that limit it is
not very harmful. The infra-red heat rays, though, are going to be a
very great menace. I can't think of any way to make them harmless. Of
course, the polished iridium shell of the ship will protect us from the
sides, as the heat will all be reflected. The difficulty will be that
the heat will fuse the window, and thus attack us. The quartz glass is
nearly opaque to heat rays, as is all glass. Being opaque, it absorbs
it, 'cuts it out' as we say. The result will be that the glass will
melt instantly, whereupon we will go very quickly. The idea of putting
a polished metal shutter before the window is the one we will have to
adopt, but we must modify it somehow. The heat rays will be turned back
all right--and so will the light rays. The question is to shut out heat
and let in light. Any suggestions?"
"I wonder if there isn't some selective reflector that we could use,
Dr. Waterson?"
"That is a good idea, Wright--but I don't know of any that will pass
all the light and reflect all the heat!"
"What is a selective reflector, Steve?"
"There are lots of things that have that property Dave, gold leaf is
one, it can transmit green light--that is you can see green light
through it, but it reflects yellow light--the complement of the
green it transmits. There are a great many organic dyes that are one
color when you look at them and the complement of that color when
you look through them. The trouble is we need one that transmits the
visible portion of the spectrum and--boy--that's it, Wright, that's
it--spectrum--take a totally reflecting diffraction grating, reflect
out all that part of the spectrum that we don't want, take what we do,
pass it through a prism to recombine it to white light, then through
lenses so we can see as if through a telescope! We will have absolutely
cold light!"
"Again it sounds good, but I'd like to hear it in English, Steve."
"The idea is to take a diffraction grating, a piece of metal with,
usually, 14,438 lines to the inch ruled on it, and previously highly
polished, so that it reflects most of the light that hits it. Now it
is reflected at different angles, so that we have a spectrum. The
spectrum spreads out light and heat waves as well--I use the reflection
grating as no material will pass the heat rays, and it then is possible
to reflect out of the car again those rays we do not want. The light,
which we do want, we will pass through a prism which will recombine
it to white light. A prism can either split up light into different
colors, or recombine them to white. Lenses then will be needed to make
the images clear. The effect will be much the same as a telescope.
And that takes care of the heat waves. The cathode rays, luckily
won't bother us for the car is already charged strongly negative, and
negatively charged electrons will be strongly repelled, as they are in
the grid of a vacuum tube, so will never hit us. The bombs constitute
the worst menace. The only defense we have against them is the very
doubtful one of not being there when they are. That is a good policy in
any case.
"As a last precaution--a bit grim--I will arrange it so that if the
'Terrestrian' is damaged to the point of utter helplessness we can, by
pushing a single button, explode the entire car--as material energy. It
will utterly destroy everything within a radius of a hundred miles, and
damage everything within a much greater radius. I believe it will not
be serious enough to change the Earth's orbit, though."
"Good--cheerful man, aren't you, Steve! Now what have we to meet that
delightful array?"
"We have things even more delightful. Our heat ray is considerably more
powerful, I imagine. It is generated by a force ten thousand times as
great. Our bombs will be worse. Wright, I wish you would make about a
hundred shells that will explode with the full thirty-five thousand ton
equivalent of dynamite. And then we will have everything they have that
is going to be effective, and have it in a more concentrated form. Can
any of you suggest anything else?"
"Steve, you said that your car was nearly pure iridium on the outside,
and that is very inert. The outside of their ship will be polished too,
won't it?"
"Probably--though I don't believe they were expecting to meet a heat
ray."
"Well, I wonder if there isn't some chemical you could spray out that
would tarnish their ship, without hurting your iridium ship? Then it
wouldn't be polished and would absorb your heat rays."
"That's a good idea, Dave. I might use a sulphide--nearly all sulphides
are colored, and form very easily and rapidly. Or I might use liquid
ozone. That will tarnish almost anything to an oxide, which is also
apt to be colored. I could certainly heat the ship that way, but I
wonder--I'm afraid that the oxide or sulphide would break down too
easily. There is only one metal that they might use on which that
would work, namely steel. Iron sulphide is black, stable, and will not
decompose readily. The oxide forms readily, is highly colored, and
will not decompose before the metal is incandescent, or even melted.
The only difficulty is that steel is so readily attacked, that they
wouldn't use it. They would probably coat it with an inert metal,
silver for instance. That forms a black sulphide very readily. I'm
afraid that won't work Dave. But Wright, I think that it would be
a good idea to develop a few of those field theory equations in a
different way. Try integrating number two-six-thirty-nine--I think
that's it--and between the limits of equation one-four-twenty-three
and zero. I have an idea that a little development of that idea will
give us a beam that will be very useful. We haven't time to make much
apparatus, but I think the result will be near enough to the space
curving projector to allow us to change the extra projectors we have in
the laboratory to fit. Also, try calculating the arrangement we will
need for the heat eliminator, please. I'm going to give Dave his first
lesson in space navigation. We'll be back about noon--if at all!" But
Gale caught the wink, so the effect was lost.
* * * * *
Ten thousand miles out in free space the practice began. As Waterson
pointed out, it would require some mighty poor handling to hit the
Earth now. For the first time in Gale's life he could practice with a
machine with no fear of hitting anything.
When the ship slanted down in a long graceful glide, to enter the
hangar doors that noon, Gale was in control. The controls of the ship
were remarkably easy to master and extremely simple. The one thing
that was hard to master was the tremendous range of power. It could be
changed in a smooth climb from a fraction of a horsepower to billions!
The first attempts had been a bit hard on the passengers, the seat
straps coming in for their share of use.
When they returned to the laboratory, they found Wright had just
prepared a light lunch, and at once began to demolish it. Six hours
between breakfast and lunch is conducive to a husky appetite.
Wright had finished the integration on the machine, and had calculated
the mathematics of the heat eliminator in a little less than four
hours. The results were very satisfactory, and in the remaining time
he had converted six of the extra projectors to their new use, and
had them ready for installation. After lunch the men began on the
construction of the heat eliminators. Two were to be installed, one
for the observer as well as one for the pilot. The heavier work of
installing the projectors and the iridium shield was reserved for later
in the afternoon.
By six that evening, the new projectors were completely installed and
the connections made, and the great iridium shield was cooling from
blinding incandescence in its mold. It would be installed that night,
but now they felt that a rest and a meal were due them. They had been
working under a great strain that afternoon, for they knew that they
must get that machine ready before the Martians reached Earth, and
there was a great deal to do. After the brief dinner they went out to
the shining "Terrestrian." As yet, the new projectors had not been
tried.
Gracefully the great shining shell backed out into the ruddy glory
of the sinking sun, the red light had turned the desert to a sea of
rolling fire, with here and there a wave that showed dark--a mound.
In the far distance the purple hills of Nevada seemed like distant
islands in this burning sea, and above it rode this lone, shining
ship, magnificently iridescent in the setting sun. Now it stopped,
hovered, then suddenly a pile of metal ingots that lay to one side of
the laboratory leaped into the air and shot toward it--then paused in
mid-air, hung poised for an instant, then sank lightly to the ground.
Now the sand of the desert began to roll into some strange wave that
began just beneath the ship, then sped away--further--till it died in
the far distance, by means of an invisible beam. A wall of sand thirty
feet high had been built in an instant, and it extended as far as the
eye could reach! Now the ship settled, and slowly, light as a feather
for all its three thousand tons of metal, it glided into the hangar.
[Illustration: _Now the sand of the desert began to roll into
some strange wave that began just beneath the ship, then sped
away--further--till it died in the far distance._]
"Man Steve, that works! How long a range has it? And please tell me
about it now you are sure it works!"
"I don't know just how long a range it has--it affected the sand as
far as we could see, and we were using very little power. It is just
a modification of the space curving apparatus. It projects a beam of
gravity, and theoretically at least it has an infinite range; and it
certainly has a whale of a lot of power. I can use a good deal of the
power too, for the strain of the attraction is taken off the mountings
and the ship, and put on space itself! The gravity projector is double
and projects a beam of the gravity ray forward and an equally powerful
beam of the space curve behind. The two rays are controlled by the same
apparatus, and so are always equal. The result is that no matter how
great a load I put on it, the entire load is expended in trying to bend
space!"
That night work was carried on under the floodlighting from the ship's
great light projectors. The entire region was illuminated, and work was
easy. Waterson had been instructed to take a rest when he seemed bent
on continuing his work. Even his great body could not keep up that hard
labor forever, and forty-eight hours of work will make any man nervous.
With a crisis such as this facing him, he certainly needed rest. He
agreed, provided they would call him in two hours. Two hours later Gale
walked about a mile from the laboratory, and called. He then returned
and continued his work on the placement of the shield. It had been
placed, polished, and tiny holes bored in it for the heat eliminator
inside of four hours. It was operated by an electric motor, controlled
from within. It could be lowered and leave the window clear, but when
in position its polished surface made it perfectly safe against heat
rays. The work had just been completed, when Waterson reappeared
looking decidedly ruffled.
"Say, I thought you two promised to call me in two hours! It's been
just four, and I woke up myself!"
"But Steve, I did call you and you didn't hear me. I didn't say I'd
wake you in two hours."
* * * * *
It was shortly afterwards that news of the coming invasion was made
public. And with the news came the wild panics, even mad, licentious
outbreaks all over the world. Man saw himself helpless before mighty
enemies whom he could not resist. Never had such a complete disruption
of business taken place in so short a time. Things were done that
night in a terrible spirit of "we die tomorrow, we play today." The
terrible jams in the cities caused the deaths of hundreds of thousands.
They wanted to flee the cities, get into the woods and hide like some
animal. Within an hour no news could reach most of them, and though
Waterson had told of his ship, told immediately, given every government
official announcements concerning it, still the mad dance went on.
But to those that had stayed near the radio sets, this news brought
relief. No television pictures of it could be broadcast for many hours,
as there was no portable equipment within several hundreds of miles,
and the men were working on the ship.
That night the three men took turns watching by the radio set for news.
The Martians were due to land somewhere on Earth that morning. It would
probably be a temporary landing in some land that was just at dawn. And
it was so. But the "Terrestrian" must not be taken by surprise.
Waterson was to have the morning watch. Unlike the others, he did not
sit by the radio set. He answered the few messages he received, but
the entire four hours of his watch he spent working with Bartholemew.
The equations he was working with seemed new, strange, and they had
terrific import to the understanding. It was but a few minutes before
the Martians landed when he had gotten the final result. At once he
called the two others.
"Wright, if that equation means what I think it does, we have something
that will give us a tremendous advantage! I feel sure that the Martians
have actually worked out the problem of the atom by pure brain
power--no machines aided them, else they too would have discovered the
secret of matter. That machine has made it possible for us to work
out problems to meet them. But as they may land any minute now, let's
begin on this. We need two of these projectors in front, and two at
the stern. If you will start on the actual projectors, I'll start the
instrument end. Come on Dave."
And so all three heard the announcement that the Martians had landed.
Twenty mighty ships had settled down in the arid land of Nevada. The
ships were a bare five hundred miles from them! The dry air of the
desert was probably best suited for Martian lungs. Army planes had
been cruising about all night waiting for the enemy, waiting to learn
definitely what they were to face. It was Lt. Charles H. Austin who
sighted them. He first saw them while still on the very outskirts of
our atmosphere, and reported them at once, turning his television
finder on them. Great balls of purple fire they seemed as they sank
rapidly through our atmosphere. The great ships floated down and as
they came within a mile or so of him, he was able to see that the
great flaming globes of light were beneath them, seemingly supporting
them. A breeze was blowing from them to him, and the air, even at that
distance, was chokingly impregnated with oxides of nitrogen and ozone,
from the forty mighty glowing spheres. They were fully an hundred
and fifty feet in diameter, but the ships themselves, illuminated by
the weird light of the glow of their sister ships, were far greater.
Each was three thousand feet long, and two hundred and fifty feet in
diameter. Hundreds of thousands of tons those mighty machines must
have weighed, and the fiery globes of ionized air that shone under the
impact of the cathode rays alone told how they were supported. Now, two
by two they sank, and came to rest on the sands below, and as they came
near the ground the glowing ray touched the sand, and for that moment
it glowed incandescent, then quickly cooled as the ray was shut off. At
last the mighty armada of space had settled on the packed sands, and
now there sprang from each a great shaft of light that searched the
heavens above for planes. By luck the plane of the observer was missed,
and the television set clicked steadily on as the questing beams were
reduced to five, and now the ground was flooded with blinding light. A
moment later the side of one of the great ships opened, and from it a
gangplank thrust itself. Then from it there came a stream of men, but
men with great chests, great ears, thin arms and legs; men that must
have stood ten feet high. Painfully they scrambled down the plank,
toiling under the greater gravity of Earth. But what a thrill must
have been theirs! They were the first men of this system to ever have
set foot on two planets! And some of those men were to step forth on a
third--the first men to visit it too!
Painfully now they were coming from their huge interplanetary cruisers,
slowly they plodded across the intervening space to their comrades,
pouring from their sister ships.
* * * * *
Then suddenly the television screen was white--a blinding searchlight
had at last picked up the plane. Wildly the pilot dived, and now there
came a picture of all those men looking upward, their first glimpse
of the works of man perhaps. But the beam that had been eluded was
reinforced in a moment--then there came a dull red beam--a flash--and
the screen was smoothly dark.
Waterson and his friends feverishly worked at their tasks. There was
no doubt about the inimical intentions of the Martians now. They had
destroyed a man without reason. And the projectors were rapidly taking
shape under the practiced hands of Wright. Dawn broke, and the men
stopped for breakfast, but still the work on the projectors was not
done. Many parts were so similar to those of the other projectors that
they could use the spare projectors for parts, many others were new.
It was shortly after breakfast that the news of the Martians' landing
came. They had started now on the famous Day of Terror. But still the
men in the laboratory worked at their tasks. The "Terrestrian" had been
christened according to plan, and was now ready to start at any moment,
but the new projectors were an additional weapon--a mighty weapon.
All matter is made of atoms, grouped to form molecules, combinations
of atoms, or a molecule may contain but one atom, as is the case
of helium. The atoms within the molecule are held to each other by
electrostatic attraction. The molecules of substances like wood are
very large, and hold to each other by a form of gravity between the
molecules. These are called amorphous substances. Water is a liquid,
a typical liquid, but we have many things that we do not recognize as
liquids. Asphalt may be so cold that it will scarcely run, yet we can
say it is a liquid. Glass is a liquid. It is a liquid that has cooled
till it became so viscous it could not run. Glass is not crystalline,
but after very many years it does slowly crystallize. The molecules
of a liquid are held together by a gravitational attraction for each
other. But in crystals we have a curious condition. The atoms of salt,
sodium chloride, do not pair off one sodium and one chlorine atom when
they crystallize; perhaps a million sodium atoms go with a million
chlorine atoms, and give a crystal of sodium chloride. Thus we have
that a crystal is not _n_(NaCl) but it is Na_n_Cl_n_. Thus a crystal of
salt is one giant molecule. This means then that the crystal is held
together by electrostatic forces and not gravitational forces. The
magnitude of these forces is such that if equivalent weights of sodium
and chlorine atoms could be separated and placed at the poles, the
chlorine atoms at the north and, eight thousand miles to the south, the
sodium, over all that distance the twenty-three pounds of sodium would
attract the thirty-five pounds of chlorine atoms with a force of forty
tons!
So it is that in all crystals the atoms are mutually balancing, and
balanced by perhaps a dozen others. The electrostatic forces hold the
crystals together, and the crystals then hold together by gravity in
many cases; otherwise they don't hold together at all. A block of steel
is made of billions of tiny crystals, each attracting its neighbor, and
thus are held together. But this force is a gravitational force.
Now what would happen if the force of gravity between these crystals
were annihilated? Instantly the piece of metal would cease to have any
strength; it would fall to a heap of ultra-microscopic crystals, a mere
heap of impalpably fine dust! The strongest metal would break down to
nothing!
Such was the ray that Waterson had developed. It would throw a beam of
a force that would thus annul the force of gravity, and the projector
had been made of a single crystal of quartz. Its effects could be
predicted, and it would indeed be a deadly weapon! The hardest metals
fell to a fine powder before it. Wood, flesh, liquids, any amorphous
or liquid substance was thrown off as single molecules. It would cause
water to burst into vapor spontaneously, without heat, for when there
is no attraction between the molecules, water is naturally a gas. Only
crystals defied this disintegration ray, and only crystals could be
used in working with it.
But while the men in the lonely laboratory in Arizona were finishing
the most terrible of their weapons, the Martians were going down the
Pacific coast.
When morning dawned on our world, it found a wild and restless
aggregation of men fleeing wildly from every large city, and with dawn
came the news that the Martian armada had risen, taking all its ships,
and was heading westward. Straight across Nevada they sailed in awful
grandeur, the mighty globes of blazing cathode rays bright even in the
light of the sun.