The director of the Lick Observatory has announced by telegraph that certain “knots” appear on Saturn's rings when they are viewed at the present time with the great 36-inch telescope. This discovery by Prof. Campbell has been confirmed by the keen-eyed Prof. Barnard from observations made with the 40-inch Yerkes lens, and also by Prof. Percival Lowell, director of the observatory at Flagstaff. In a letter to the writer, Prof. Barnard states that these condensations were first seen by him on July 2. They disap peared when the sun came into the plane of the rings; but reappeared on October 13. Since then they have been easily visible. Percival Lowell, so well known from his observations on Mars, believes these knots to be due to a falling in of the rings on the planet, itself, thus pointing the way to the ultimate de struction of one of the most beautiful objects of the starry heavens. Such an opinion, however, seems to be at variance with the ideas held by most of the rest, of the astronomical world. Early in October this year, Saturn presented the strange appearance of being entirely without rings, even when viewed in the most powerful of telescopes. No great catastrophe had happened on the distant, planet, nor had "Saturn swallowed his children," as is told in the legend; but the disappearance was due to the simple fact that on October 4 the earth passed through the plane of the rings, giving us an opportunity of looking at them edgewise. If a small model were constructed of Saturn, on a scale of 10,000 miles to the inch, the planet itself would appear as a somewhat flattened ball ??/ inches in diameter, while on the same scale the rings would have a diameter of 17 inches, but, they would be no greater in thickness than a sheet of paper. Nearly nine hundred million miles away from the sun, nine times farther off than the earth, it, takes Saturn twenty-nine and a half years to make one revolution about the sun. Twice in this time, or every fifteen years, the earth passes through the plane of the rings, which though 170,000 miles in diameter, are probably not more than 100 miles thick. Com pared with the eight, hundred million of miles that, we are distant from Saturn when nearest it, 100 miles is too'small an edge (1/40 of a second of arc) to be seen even in a big telescope. Since those rings were first discovered in the tiny telescope used by Galileo nearly three hundred years ago, they have been a constant enigma to astronomers of all time, and it has been very difficult to explain how it is that this thin disk can hold itself together without breaking up while it rotates quickly about the planet. At the present, time, a month after .the earth has passed through the plane of the rings, they are seen not quite edgewise, and appear in a powerful tele scope as a thin line of light. A splendid opportunity is thus afforded of discovering wheth er the rings are everywhere of the same thickness. As knots are seen along the thin thread of light, we must perforce conclude that the rings are not quite flat, but that they have condensations here and there, and that the particles that make them up crowd together more at, some places than they do at others. This is indeed no new discovery. Nearly half a century ago Otto Struve suspected that he saw bumps on the ring system, and the observations of 1907 are but a confirmation, using better telescopes, of what Struve saw. Moreover, Prof. Lowell's idea that, the rings are falling in upon Saturn was proposed by Struve after a compari son of his drawings with still earlier ones. But, the rings have now to our knowledge lasted three hundred years, and no real change in them has ever been noticed. The fear among astronomers and star gazers that this unique feature of the solar system may come to an end, appears to be well-nigh groundless. Sixty years ago the celebrated Clerk Maxwell showed that, it was impossi ble for the rings to be a continuous solid and rotate about Saturn in obedience to the law of gravitation, but at the same time he pointed out that these rings must, consist, of thousands and mil lions of small satellites, each rotating independently about the planet, those nearest to it moving fastest. In 1895, a remarkable confirmation of this idea of Maxwell's was obtained from rather an unexpected quarter, viz., by means of the spectroscope. That the spectroscope, which tells us of the colors of the spec trum, and of the metals which constitute the far-off sun and stars, should tell us whether Saturn's rings are one body or many, seems a far cry; but, such is the case. This it does by measuring the motion of the rings. If they are a continuous body, then the farther off from the planet, the faster they must move in miles per second; but if the rings are a collection of satellites, then those nearest, the planet, move the fastest, just as on a large scale Mercury, because nearer the sun, moves faster than Jupiter. The ac companying illustration gives a reproduction of one of the most, marvelous photographs of modern astron omy, Keeler's spectrum of Saturn's rings, with the spectrum of the moon above and below for compari son. If the rings were solid throughout, each line of the spectrum of Saturn and its rings would form a continuous straight, line inclined slightly to the ver tical. Such is not, the case, as is evident from a close inspection of the photographs. The change in direc tion of the spectrum lines proves clearly what Maxwell had shown from pure mathematics, that, the rings are a system of small bodies, or meteorites, or satellites, each rotating independently about the planet. As a consequence of this mathematical theory, it can be shown that the satellites are liable to crowd together in certain places, even departing slightly from the average plane, but this does not point to the end of the ring system. It seems quite safe to predict that Saturn's rings will appear to our grandchildren just as beautiful as they do to us now. The Overcoat. The season of overcoats is approaching, says the Lon don Lancet, and probably in no other department, sar torial is there exhibited so much indifference to hy gienic considerations. The greatest fallacy of all, perhaps, in regard to the choice of an overcoat, is that the terms "weight" and "warmth" are synonymous. As a matter of fact they are nearly always diametrically op posed. Heavy materials are often good conductors of heat and are cal culated therefore to allow the heat of the body to escape, while light ma terials are bad conductors and so pre serve the heat and energies of the body. Moreover, the heavy overcoat is a tax on the resources of the or ganism and destroys the economy which a good insulating cloth is in tended to secure. Further, heavy ma terial encouragea an uncleanly and unhealthy state of the body chiefly by imprisoning the exhalation of the skin. That cloth is best, therefore, which gives the minimum of weight and the maximum of warmth while being por ous enough to admit of ventilation. It is not gener ally realized that, in protecting the body from the dissipation of its own heat,—i. e., from cold—-clothing really serves as an economizer of fuel—that is, food. Could we accustom ourselves to wearing no clothing at, all under cold climatic conditions we should have to consume much more food than we do in order to compensate for the rapid loss of heat which would happen if the body were not wrapped in non-conduct ing materials. This point, needs to be borne in mind by those who advocate the banishment of the over coat. It, is, of course, possible to dispense with an overcoat, provided that the clothes worn are particu larly warm. The overcoat, however, offers the de cided advantage that it can be superimposed over a comparatively light, suit of clothes and thus while preventing the escape of heat provides also an air space between the ordinary clothes and itself—an air space which is open to ventilation. There seems to be little doubt that a well-chosen overcoat surround ing a warm but, light suit of clothes is for the rea sons just given much more comfortable than a heavy suit of ordinary clothes. There is another important point about the qualities of an overcoat, and that is in regard to the color of the material. The choice of a somber hue—black, dark gray, dark brown, or dark blue—is totally opposed to scientific indications. The polar bear is not provided with black fur; if he were he would not, be able to defy the cold with that, im punity which he - does. Light, colored material, as a matter of fact, does not so easily give up its heat as does dark material, and this would appear to teach that our notions as to the suitability of color of gar ments for winter wear are illogical. Fashion and custom bind us hard and are seldom on all fours with reasonable ideas. If he would follow the dictates of science and common sense, the purchaser of winter clothing would choose, if he were able to do so, garments of a light rather than a dark hue. And why should everyone be clothed in a funer eal type of material just when winter sets in, when every effort is necessary to compensate for the dreariness and darkness of its days? New Fuel Made from Fruit Seeds. A new kind of fuel will very soon be manufactured in Los Angeles, for which it, is claimed that it will pro duce no odor, smoke, or gases and very little ashes from its consumption, that no kindling will be needed to set it on fire, and that two bricks will last prac tically all day in a stove or grate. It is composed of fruit pits from the can neries, mostly peach and apricot. About sixteen tons of these pits are to be used a day at the factory. The shells are broken up by a machine, and the inside pits, or kernels, are shipped to France, where they are used in the manufac ture of prussic acid. These are mixed with other materials, including crude petroleum, or brea, a residuum deposit from the oil fields, planing mill shavings, and pulp from the olive oil mills. In connection with this fuel, "smudge" fuel will also be made for producing dense smoke. This will be used in orchards to preserve trees and fruit from frost, and has already been put to excellent ser vice on a number of big ranches.
This article was originally published with the title "“Knots” in the Rings of Saturn"