A. Frederick Collins

“ This double motion of the eggshell is exactly like the double motion of a planet—each one turns on his own axis and each travels round the Sun in its own orbit; moreover, all the planets travel round the Sun in the same direction, the nearest planets taking the shortest time to complete the circle or orbit, while those farthest away take the longest time to go round their orbits just as we might expect them to do. ”

“ When I tell you that waves in the ether which are sent out by the light of a candle or the Sun are only about 15 ten-millionths to 30 ten-millionths of an inch in length, and that the holes, or pores, in the glass and the cornea and lens of the eye, and which are full of ether, are much larger, you can readily understand that the ether waves which we call light can merrily pass through either glass or the eye and that there is nothing in the way to stop them. ”

“ We know that, roughly, a year is the time it takes the four seasons to come and go, and that this is done when the Earth travels once round the Sun; that the month is based on the time it takes the Moon to travel once round the Earth; that the week has nothing to do with the Sun, Earth, Moon or Stars, but is a pure invention, and, finally, that the day is the time it takes the Earth to turn once round on its axis. ”

“ By pointing your camera toward that part of the sky and during that time of the year when there are showers of meteors, and opening the shutter of your lens, you stand a chance, though it is not a very fat one, of catching one of these wily shooting stars on your plate, and if you do succeed—well, you will have a picture that is a curiosity. ”

“ Take a look at Jupiter some night when he is moving across any of the constellations and he will seem to be a part of it; this is the reason we speak of the Sun or a planet as being in a certain constellation at a given time.
The stars forming the background of the Moon and the planets can always be seen, for we are then looking at them from the dark side of the Earth, but they cannot be seen when they form the background of the Sun, for the stars are on the other side of him when he gets between us and them and he shines in our eyes. ”

“ In starcraft, when the Earth passes across the Sun, and the Moon is hidden in its shadow, we say that it is an eclipse of the Moon; or when the Moon passes across the Sun and covers it we say that there has been an eclipse of the Sun. ”

“ A few nights later the Moon will be seen, over in the sky toward the east; its crescent shape grown into the first quarter, and the Moon looks as if it was split in two. As the nights go by the Moon waxes until it is gibbous and finally the full Moon—with the man in it—stands out round and clear and bright. ”

“ The bright point of light which thus seems to us to be a star when we look at it with the naked eye is really another world, or planet as it is called, and very like our own Earth. To prove that this moving point of light is really a world, or planet, and not a distant star, all you need to do is to look at it through a pair of opera glasses, or a small telescope, when it will be seen to be a round body, whereas a star when viewed through the greatest telescope is never larger than a mere point of light. (See Fig. 50.) ”

“ Combustion, or burning is a chemical action and can be explained by saying that it is the combining of a substance with oxygen, or other substance with the production of heat and light.
The only difference between heat and light is that of wave length as we shall see presently, and the length of heat waves and of light waves depends entirely on the rapidity with which the atoms vibrate, or the frequency of vibration, as it is called. If the atoms of gas move slowly heat is sent out and if the atoms move rapidly the heat grows more intense and light is radiated. ”

“ How Heat and Light Travel.—While the little motions or vibrations, of the particles, or atoms, of gas forming the flame of a [Pg 124] candle, the Sun, and other heat and light givers could go on just the same we could not feel their heat or see their light without something or some kind of a substance which would connect them with our bodies and our eyes, like a wire connecting a push button with an electric bell. And there is something which connects us with the most distant stars and that something is called the ether. ”

“ Once you have found Orion you will never again require the help of a star chart to locate him, but it is a good plan to look him up as often as you can, and to draw the imaginary line through his sword and on to the North Star, for should you ever lose your way or want to find the north and the North Star should be hidden by clouds a line through the Sword of Orion when Orion is in the south will direct you as certainly as the needle of a compass. ”

“ When the air is set in motion by the vibrations of a bell, or any other device for producing from 32 to 40,000 vibrations per second, we can hear it, and when the air moves as a mass, as when the wind blows, we can feel it. Air forms a layer around the Earth that is between 200 and 300 miles thick, but out in the great space beyond there is no air. Yet the space is not empty, but it is filled instead with a substance called the ether. ”

“ But the point is this: an astronomer can obtain the time from watching a star cross the meridian much more accurately than he can from the Sun, because a star is a mere point of light, and it is easier for him to calculate the mean solar time from the transit of a star than it is for him to go to bed, and besides he would rather do it, too. ”

“ If a meteor is small it is entirely burned up before it reaches the Earth and all we see of it is a bright streak of light. If a meteor is large enough only the outside of it is burned and it will, in consequence, reach the Earth, when it becomes, as explained in the last chapter, a meteorite.
Meteors and meteorites produce a very bright light, burning as they do in the oxygen of our air, and though they are very close to us they are so small we cannot feel any heat sent out by them. ”

“ The Earth Turning Round the Sun Makes the Seasons.—We have seen how the days and nights would be equal all over the world if the equator of the Earth was in a plane with the Sun, but since the Earth is tilted the days and nights are unequal except twice a year, and this is when the places where the ecliptic and the equator cross each other are facing the Sun. ”

“ While the Earth has cooled off until it is possible for us to live comfortably on its crust, it is still warm outside and very hot inside. This is proved by volcanoes which throw out white hot lava and gases when they are in eruption.
If it had not been for the light and heat of the Sun in the past ages there never could have been any kind of life on the Earth. The Earth is just as dependent on the Sun now as it was in the past, and if he [Pg 67] should fail to shine on our world for even a little time everything would die. Fig. 70 is a cross section of the Earth. ”

“ A variable star is one whose brightness changes from time to time. A great many variable stars are known, but very few of them can be seen with the naked eye. There are different reasons given for a star varying in brightness. Our Sun is a variable star, and we are told that this is due to his spots. Another type of variation is perhaps produced by pulsations—the star periodically expanding and contracting. Again a double star formed of two bright stars which revolve round each other, as many double stars do, may eclipse one another, and this would cause a change in brightness. ”

“ When his master returned the boy showed him what he had done and it was not long before the great Galileo had a telescope and was startling the world by his wonderful discoveries of the moons of Jupiter, the rings of Saturn, the phases of Venus, the spots on the Sun and a hundred other wonders of the sky.
A telescope is an arrangement of lenses in a tube for making the image [Pg 137] of a distant object larger on the retina of the eye, or, as in the case of the fixed stars, for making them brighter. ”

“ Lenses are pieces of glass having curved surfaces. When a beam of light passes through a lens it is also bent out of its original direction, or refracted.
A convex lens, see Fig. 146, is a lens which is thicker in the middle than it is at the edges. A convex lens is used for magnifying an object; or for forming an image so that it can be magnified by another lens as in a telescope, for forming an image on the screen of a camera, and for bringing the heat waves of the Sun to a focus, as with a burning glass. ”

“ These bright patches, then, which form the Milky Way, are really groups of stars or star-clusters, and when some of these clusters are photographed through a telescope as many as 15 or 20 thousand stars can be counted, while the real number of stars that lie beyond and which cannot be seen is past all calculation, and, just think of it, every one of these stars is a Sun as large or larger than our Sun! ”

“ Now, a comet, however great it may grow to be, never bursts into view, big, bright and beautiful, but when one is found it is usually seen as a little, dim patch of light, and it would quite likely be mistaken for a nebula, if it did not move along so swiftly. ”

“ In the gas light the gas, which is made of coal or other matter, is forced out of the jet under pressure and this gives a bigger and better flame than the oil lamp; and, as the oil lamp is better than the candle, so the gas jet is an improvement over the oil lamp.
Now the Sun, and this is also true of most of the stars, is so large and hot that if any solid matter, such as iron and other metals could be thrown into the Sun they would not only be melted but instantly changed into gases. Further, the Sun is so hot that the materials cannot combine with Oxygen—in other words they cannot burn. ”

“ When the atoms of a burning gas vibrate just fast enough to produce light the color of the light is red; when the atoms vibrate still faster the color of the light is green and when the atoms vibrate very fast the light sent out is violet, so we see that not only do the vibrating atoms send out light but that the rapidity, or frequency with which they vibrate makes, or determines, the color as well of the light which is sent out. ”

“ You can photograph the Sun with an ordinary camera and make his disk [Pg 188] as large as you want to, but you will get nothing more on your plate than a white spot. The Moon can likewise be photographed, but if you focus it sharp on the plate it will not be much larger than a mere point of light, and if you get a disk large enough to see there will only be a small white spot on your finished print.
To make good photographs of the Sun, Moon and planets, a big telescope driven by clockwork to offset the turning of the Earth is needed. ”

“ Now, meteors, fireballs, shooting stars and meteorites are all one and the same thing to start with and they have their beginnings when some comet goes to pieces.
After a comet breaks up, the pieces of stone and iron which form it still travel round in the same orbit. Some of these pieces may get within range of the Earth’s force of gravitation when they are drawn to it, and on striking the air they are intensely heated by the friction, and if they are small they burn up before reaching the ground. ”

“ The illusion is much more complete when we are seeing the stars, for the motion of the Earth as it spins on its axis and shoots round the Sun in its orbit is so steady that we cannot notice it; for this reason it seems as if it is the stars which are moving and that we are standing still. ”

“ While we can see the light of a comet we cannot feel its heat, for a comet is too small to send its heat waves through such a great distance.
Just as a match is lit by striking it, so meteors are set on fire by striking the air. Meteors are made up of the same kind of matter as comets and when these shooting stars come within the attraction of the Earth the friction caused by the meteor rubbing against the air is so great that an intense heat is produced and the gases burst into flame. ”

“ When we look at the surface of the Earth by daylight we see the sand and stones, grass and trees, houses and other objects by the light which is reflected, or thrown back from the surface of these things by the Sun. ”

“ The meteors, or little planets, making up the nebula, attract each other, like all other bodies, and when they get close enough they are drawn together and dense masses of matter, or cores, are built up. The largest core is seen in the center of a spiral nebula, and as it becomes more compact it grows hotter and a Sun is made, while the other and smaller cores turn round it and attract little planets to them. And so the cores grow in size, and with more and more weight bearing toward their centers the gases are forced out and these make the air and water. ”

“ Fig. 147.—Concave Lens.
Of course we all know that when a candle or a gaslight or the Sun shines on an apple or any other opaque object—that is, an object that will not let the ether waves go through it—the light is cut off back of it and this dark space is called a shadow; this is also true when the Sun shines on the Earth, or on any of the other planets or their moons.
There are always two parts to the shadow of an object unless the light is a mere point or the object is very close to the screen, or surface on which the shadow falls. The dark part of the shadow is called the umbra. ”