peak about DOME OF THE SIXTY-INCH REFLECTING TELESCOPE. MOUNT WILSON, CALIFORNIA constructed six thousand feet high, near Pasadena, California. Tons of material were carried up the narrow and perilous mountain path on the backs of burros. Later an automobile road was at great expense. Now the observatory and the experimental laboratory and instrument shops in Pasadena have in the aggregate a staff of nearly sixty persons. These are not only assistants and computers, but many are men of high scientific standing. Some of the foremost astronomers of Europe have considered it an honor to work there. One of Hale's most valuable characteristics is his ability to get other men to work, and to make those who work under him feel that they are working with him and not the world been erected on the mountain, with a still more powerful one nearing completion, but almost countless instruments of entirely new types have been designed, constructed, and used. The telescopes are so different from those of traditional type that their character would not be suspected at first sight. One is in a long horizontal building down which the rays from celestial objects are reflected by a suitably rotating mirror. In the interior. the light is brought to a focus by lenses. or a concave mirror and observed, photographed, or passed through a spectroscope, as the investigation under way may require. Another observatory consists of a tower one hundred and seventy-six feet high over a well seventy-eight feet deep. A rotating mirror at the top of the tower reflects the rays from celestial objects down through an enclosed shaft into the well, where they are used in various ways. The advantage of the well is that in it the temperature remains almost constant, a condition that is very important in delicate spectroscopic observations. It is necessary that the rotating mirror at the top of the tower shall not be shaken by winds or moved by changes of temperature in the supporting steel work. To obviate such possible disturbances, the optical parts are carried on steel supports enclosed, without contact, within the supports of the dome, running from. the ground to the top. Just as a modern locomotive is more complex than the ox-drawn wagons which first crossed our western prairies, so the equipment of a modern observatory is more complicated than that of a few generations ago. Then an equatorially mounted telescope and a meridian circle constituted nearly all the requisites for any kind of astronomical work. Now an immense variety of instruments are necessary, as has been seen; but in addition to those which have been mentioned, the Solar Observatory maintains THE ONE-HUNDRED-FIFTY-FOOT TOWER TELESCOPE OF THE SOLAR OBSERVATORY ON MOUNT WILSON, CALIFORNIA in Pasadena a splendidly equipped physical laboratory in which experiments are made in electrical furnaces in vacua or under high pressure, or in a magnetic field, for the purpose of assisting in interpreting celestial phenomena. Then an astronomer drew a diagram of what he saw. Now the photographic plates are studied by experts in the laboratory under microscopes. Then the observer reduced his own observations by the simple processes which were adequate. Now the more complicated data are analyzed by the staff of a computing bureau under the guidance of an expert director. Then the discovery of a new world could be announced in the headlines of a newspaper. Now the intricacies of stellar classification, star streaming, and the magnetic field of the sun require books for their explanation, and can be fully understood only by those who have a considerable knowledge of science and are able to devote much time to study. The scientific product of the Solar Observatory more than justifies the hundreds of thousands of dollars it costs. But little of it is of the sensational type, such as the discovery of a canal on Mars, which makes a good item for the evening paper. The problems are profound questions respecting the dynamics of the sun, the structure of the stellar universe, and the laws of evolution of the celestial masses. It must not be supposed that Hale is known as a scientist chiefly because he has built three observatories, two of which are among the very largest in the world, or because he has had any primary interest in these undertakings. This work has been only a necessary prerequisite to the attack on the scientific problems he has had in mind from his college days. The satisfaction that has come to him from seeing his boldest dreams in observatory building realized cannot repay him for the precious years they have cost. When he might have been working on the magnetic state of the sun and the causes of the awful storms that rage on its surface, or analyzing, at night, the light from the stars in cover the mode of their evolution, he was compelled to give weeks and months and years on the endless and often petty details incident to great building oper ations. Very early in his career Hale made an invention of the highest importance, known of known as the spectroheliograph. Its purpose is to photograph the sun with the light which comes from a single element. The basis of spectrum analysis is the fact, verified in the laboratory, that each of the chemical elements when incandescent in a gaseous state gives only one or more definite kinds of light which are not emitted by any other element under like conditions. The spectroscope separates the light, coming from a mixture of substances, out into its constituent parts. The spectroheliograph enables the astronomer to use a single one of the many kinds of light which such a body as the sun may radiate, and, by ingenious EUROPE'S ARMIES A By J. A.White SUBSIDY may be secured for almost anything, if it has a probable military use. From ship subsidies, the powers went to subsidizing motorcycles and motor trucks. The French, who are the true Yankees of Europe, started the game and the other great powers quickly fell in line. The Germans, however, have worked out the best system; it is based not only on their own experience, but on that of the French. Americans are specialists in athletics, business, and types of invention having chiefly to do with business. The Germans, on the other hand, are specialists in war and patriotism. It is possibly not so much American enterprise and acumen that makes them leaders in business, as the fact that so much of the energy of Europe has been devoted to preparation for war. The way the Germans have BRITISH PAY FIVE HUNDRED FIFTY DOL LARS SUBSIDY ON MOTOR TRUCKS It is paid in installments every six months for three years, the machine to be at the service of the War Office in time of national stress. seized and held the trade in South America is merely an indication of what they might do if there should eventually be a general disarmament. There are a number of standard designs for motor trucks that have been most rigorously tested and approved by the German war office. For some time past any citizen within the Empire who intended to purchase one of these motor trucks notified the government. Experts were sent to give the car a thorough trial to make certain that it was in no wise defective. If it passed the test, in every respect, the purchaser of the machine was given one thousand dollars as a bounty, or subsidy, with which to make his first payment. At the end of the second year he was to receive two hundred and fifty dollars more, and a like sum at the end of the three successive years, so that at the termination of five years he would have received in The fleet of motor trucks buzz in the rear of the French army. They can handle a load and then catch up with the ENGLISH TRUCKS AT THE SERVICE OF THE ARMY The promptness with which these motor wagons were got ready for service in transporting troops and supplies, at the outbreak of the war, showed the wisdom of the English Government in adopting the subsidizing scheme. When the war started, hundreds of the trucks were put in use. |