Two hundred years before Christ, the great mathematician Archimedes said, “Give me a fulcrum and I will move the earth!” Our earth is a huge ball, about eight thousand miles in diameter and it weighs some six hundred trillion or sextillion tons. (To remember this place twenty-one ciphers after the six--6,000,000,000,000,000,000,000.) It is composed of rock, sand and water. Seventy-three per cent., or about three-quarters, of the earth is water--the balance, twenty-seven per cent., or about one-quarter, is solid matter, that is, rock or sand. The entire surface of the earth measures nearly two hundred million square miles and in contents the earth is about two hundred and sixty billion cubic miles. The earth is covered with a thin envelope of air and clouds which travels with the earth. If such was not the case, a balloon rising in Europe could stay up three hours, and without moving from its position, land in North America. Furthermore, if the air blanket did not travel with the earth, it is probable that the earth would burn up, since the friction between the earth’s surface and the air would develop great heat, a heat in which nothing could live. The earth traveling in a magnetic field like that of a huge dynamo, speeds around its own imaginary axis, which lies at an angle of 23½ degrees, once in twenty-four hours. This is at a speed, when one stands at the Equator, say in North Africa, of more than a thousand miles per hour, whereas a few feet from the poles, the speed is not more than nineteen feet in twenty-four hours. As it whirls around itself, the earth rushes through space in orbital motion, in an easterly direction around the sun, at a velocity of eighteen and a half miles per second, or six hundred and sixty-six thousand miles per hour, a speed that is about fifty times as great as that of the swiftest cannon ball. We earth people are entirely unconscious of this motion, since it is perfectly steady and without a jar. Once in a year, that is in a little more than three hundred and sixty-five days, we travel around the sun, but remain away from that planet at a distance of about ninety-two million miles. As we look upward at the sky at night we see, in all directions, the countless stars. Most pronounced among them and looking much the same, though of a different nature, are the planets and once in a while a comet. A few faintly shining clouds are seen--the Milky Way and Nebulae. The most striking, and yet the most insignificant of them all is the moon. During that period known as “day” to us the sun alone is visible, flooding the air with its light and thereby hiding all other heavenly bodies from the vision of the unaided eye--a few of them being visible through a telescope.