1780 The Leader 1905 for 125 Years A MATTER OF HEALTH Walter Baker&Co. ROYAL Registered, U. S. Pat. Off. Chocolate & Cocoa It is a perfect food, highly nourishing, easily digested, fitted to repair wasted strength, preserve health and prolong life. A new and handsomely illustrated Recipe Book sent free. Walter Baker & Co. Ltd. Established 1780 DORCHESTER, MASS. 45 Highest Awards In Europe and America BAKING Absolutely Pure HAS NO SUBSTITUTE A Cream of Tartar Powder, free from alum or phosphatic acid ROYAL BAKING POWDER CO., NEW YORK. vose PIANOS Established in Eighteen Hundred and Fifty-One The Unvarying Superiority of Vose quality, maintained for more than half a century, has made vose pianos Impregnable in their By our easy payment plan, every family in moderate circumstances can own a Vose piano. We allow a liberal price for old instruments in exchange, and deliver the piano in your house free of expense... You can deal with us at a distant point the same as in Boston. Send for Catalogue and full information. Vose & SONS PIANO CO. 161 Boylston Street, Boston, Mass. A faithful pen's the noblest gift Waterman's Fountain Pen that it is faithful to the last drop. For sale at all dealers, but be- L. E. Waterman Co., Main Office, 173 Broadway, N. Y. 138 Montgomery St., San Francisco. 8 School St., Boston. 136 St. James St., Montreal. THE M.C. B. ASSOCIATION RECOMMENDS A KNUCKLE OPENER "Which will throw the knuckle completely open and operate under all conditions of wear and service." THIS RECOMMENDATION Exactly DESCRIBES THE OPER. ATION OF THE PITT COUPLER O make the operation of opening the knuckle by means of a "Kicker" as safe as it has always been by hand it is essential that the "Kickers" should work every time. The failure to do so has been the cause of many serious accidents. We find many switchmen who, taught by experience, disregard the presence of any "Knuckle-Opener" or "Kicker" and open the knuckle, always, by hand. Thus, in a very practical way is made manifest the necessity for a safe design in a "safety-appliance." The "Knuckle Opener" in the Pitt Coupler is positive in its operation and pushes the knuckle open to its fullest range of movement either from a fully closed position or from any partially open position regardless of rust. With the Pitt Coupler the switchmen will never be obliged to reach in-on sudden impulse-at the last moment and when the car is in motion to open the knuckle by hand. Manufactured Only by The McConway & Torley Co. PITTSBURGH, PA. From Scientific American, by special permission of Munn & Company. No conception whatever can be had of the magnitude of the visible universe until the distances of the stars are known. None of the millions of the human beings that have lived and died knew the distance of even one star from the earth until within the last seventy years. Το all who lived before the advent of modern astronomy, the stars were points in a rigid firmament, only a short distance "above" the earth. They were made to give light to the earth's inhabitants, a belief incredible to relate, still lingering in the minds of some. Before A. D. 1542, ignorance was at its lowest depth. But in that auspicious year Copernicus gave his book to the world teaching that the earth revolves around the sun. Of course the people raised strenuous opposition. This was expected. But unrest and perplexity filled at least one of the ablest minds in Europe, that of Tycho. From the days of Aristotle and Ptolemy, the theory that the sun revolves around the earth dominated men's minds. Not one law could be discovered so long as it was believed that the earth is the center of the universe and at rest. Copernicus upset this doctrine, and made the sun the center of planetary motion. The great Tycho Brahe actually rejected this basic truth of nature. His mathematical powers must have told him that Copernicus was right in asserting that the earth moves around the sun. But when he saw that No. 12 if this is true, the entire orbit traversed by the earth around the sun, that mighty ellipse, shrinks and subsides into nothingness, his mind was simply submerged by the immensity of the idea, and all it led to. For twenty years he toiled in an observatory making measurements with every accuracy possible without telescopic aid. And he failed to detect the slightest displacement of any star throughout the year. For it is certain that if the earth moves around the sun, the stars in position at right angles to the plane of the orbit must shift to and fro at intervals of six months corresponding with the displacement of the earth from side to side of its majestic pathway. So he taught that the earth is at rest. He could not force himself to admit that the diameter of the orbit of the earth as seen from any star is next to nothing, and that the earth is next to nothing, and man an infinitesimal so minute that no combination of figures is able to tell how small he is. Tycho could measure four minutes of arc with some approach to accuracy; still he could not detect the slightest displacement of a star. He at once knew that the stars were not less than one thousand times farther away than the sun. Saturn at that time was the known limit of the solar system, and if the hypothesis of Copernicus were true, the stars must be at least one hundred times more distant. This vast space again over whelmed his mind. He argued that Nature would not so waste space. But Copernicus advanced arguments that Tycho could not overthrow, so Tycho compromised. He made the five planets revolve around the sun, and the sun around the earth, immovable in the center of the universe. At that epoch, it is probable that if Tycho had had an instrument capable of measuring one second of arc and had he tested it on any star, the Copernican system would have been crushed. For he would have discovered that the stars do not shift even one second in six months. For with an annual shifting of one second of an arc the star in question would have been known by Tycho to be 206,265 times more distant than the sun. Medieval minds would have collapsed and an indefinable fear would have settled down on mankind, when thinking of its littleness. Matters move on apace. Tycho died, and the Copernican doctrine spread. Then came Galileo with his little telescope, and pointed it full on the distant stars in A. D. 1610. This aroused Europe, and the exciting search began. Astronomers now armed with instruments that magnified were able to detect far less displacements of stars than could be detected by Tycho. And they began to watch. Thus they noted the position of a star, its direction in space and its distance from other nearby stars and recorded these determinations. In six months they repeated the process with great care. They were dumbfounded. Although the earth had moved from its first place, by the diameter of its mighty orbit, no trace of motion, however minute, could be detected in the stars, even in a telescope that magnified two hundred times. A number of great astronomers tried their hands from 1542 to 1650, a period of 108 years, with total failure as a result, Bradley and Molyneaux detected a motion of stars; but in a direction opposite to any caused by the motion of the earth. This was the aberration of light. Other astronomers after elaborate trials with the most nearly perfect instruments that could be made, failed utterly. About 1650 the micrometer was in vented. This is an instrument to be attached to the eye-end of a telescope. It contains fixed and movable spider's threads, and it can measure excessively small angles and intervals. It was crude at first, but during the succeeding two centuries the most accomplished mechanics applied their skill in making it as perfect as anything wrought by human hands. At present it is able to measure the diameter of a spider line. The object of making it of such extreme accuracy is to be able to measure the diameter of the earth's orbit as seen from the stars. For next to nothing is the diameter seen from stellar distances. Passing the labors of the Herschels and the Struves and many other eminent astronomers, who made use of every conceivable method of finding the distance of a star, we descend rapidly to Bessel and Henderson, two illustrious observers, who finally succeeded, and reaped the reward of two centuries of labors surpassing those of Hercules. Bessel, at last, in 1840, found the distance of the star 61 Cygni. He used a different kind of telescope, the heliometer with a divided object glass. He employed the method known as triangulation. He selected. two stars adjacent to 61 Cygni and measured a network of triangles, whose sides were the distances from star to star and from each star to 61 Cygni. He repeatedly measured these angles from October, 1837, to March, 1840, and had the extreme good fortune to see 61 Cygni move. And the direction of motion was as it should be, if caused by the annual circuit of the earth. He found that if we go to 61 Cygni, turn and look this way with a powerful telescope and micrometer, the distance of the earth from the sun would measure 0.3483 second of arc. The arc of any circle in length equal to the radius contains 206,265 seconds, which divided by 0.3483 equals 590,000. That is, the star is at the colossal distance of 590,000 times that of the sun. To reduce this to miles, multiply by 93 million. The result is so enormous that the ablest mathematicians never try to begin to think about it. Light, known to move with the unthinkable speed of 186,000 |