How far away from us is the sun? Are we to answer just as we think, or just as we know? On a fine summer day, when we can see him clearly, it looks as if a short trip in a balloon might take us to his throne in the sky, yet we know--because the astronomers tell us so--that he is more than ninety-one millions of miles distant from our earth. Ninety-one millions of miles! It is not easy even to imagine this distance; but let us fancy ourselves in an express-train going sixty miles an hour without making a single stop. At that flying rate we could travel from the earth to the sun in one hundred and seventy-one years,--that is, if we had a road to run on and time to spare for the journey. Arriving at the palace of the sun, we might then have some idea of his size. A learned Greek who lived more than two thousand years ago thought the sun about as large as the Peloponnesus; if he had lived in our country, he might have said, "About as large as Massachusetts." As large as their peninsula! The other Greeks laughed at him for believing that the shining ball was so vast. How astonished they would have been--yes, and the wise man too--if they had been told that the brilliant lord of the day was more than a million times as large as the whole world! LESSON XXX IVORY How many articles are made of ivory! Here is a polished knife-handle, and there a strangely-carved paper-cutter. In the same shop may be found albums and prayer-books with ivory covers; and, not far away, penholders, curious toys, and parasol-handles, all made of the glossy white material. Where ivory is abundant, chairs of state, and even thrones are made of it; and in Russia, in the palaces of the great, floors inlaid with ivory help to beautify the grand apartments. One African sultan has a whole fence of elephants' tusks around his royal residence; the residence itself is straw-roofed and barbarous enough, both in design and in structure. Yet imagine that ivory fence! The elephants slain in Africa and India in the course of a year could not furnish half the ivory used in the great markets of the world during that time. Vienna, Paris, London and St. Petersburg keep the elephant-hunters busy, yet it is impossible for them to satisfy all the demands made upon them, and the ivory-diggers must be called upon to add to the supply. Every spring, when the ice begins to thaw, new mines or deposits of fossil ivory--a perfect treasure of mammoths' tusks--are discovered in the marsh-lands of Eastern Siberia. There are no mammoths now--unless we call elephants by that name; yet their remains have been found upon both continents. In the year 1799, the perfect skeleton of one of these animals was found in an ice-bank near the mouth of a Siberian river. As the vast ice-field thawed, the remains of the huge animal came to light.