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Show ASTRONOMICAL REVIEW FOR 1881. The following interesting facts, regarding the astronomy of the past year have been sent us by Prof. Lewis Swift, of the Warner Observatory, Rochester, N. Y. The astronomical events of the year 1881 will long occupy a distinguished place in the annals of astronomy. In the matter of comets, especially, it has been an exceptionally good year. Since the commencement of this century, there have appeared, and have been carefully observed, and their orbits computed, nearly 200 comets-an average of about one in five months, but in the interval between May 1st and November 16th, (only six and a half months) seven comets were discovered two of which were visible to the naked eye, one of them so conspicuous as to take rank with the most remarkable of those of modern times. Immediately upon the announcement of the discovery of a comet-whether made in this country or in Europe-special circulars have been printed and gratuitously and widely distributed by the Rochester Astronomical Society. By means of these Circulars-which are issued in less than one hour after receipt of news-every newspaper and every professional and amateur astronomer in the United States is informed of all the known details which the discoverer is able to give. As the year is nearing its close, it seems desirable that a resume of the comets in the order of their discovery, be made, and also some special facts regarding each be presented to the public which could not be done within the limits of the circulars which were sent out, before their orbits had been computed, or any of their peculiar characteristics ascertained. My retrospect must necessarily be brief and confined chiefly to the comets of the year 1881, which, in point of number have but twice been exceeded during the history of astronomy. Of the seven, five were discovered in the United States, a number equal to one fifth of all that have ever been detected on this continent. This sudden increase of American discoveries is, no doubt, largely due to the prize of $200 for the discovery (in this country and Canada) of each new comet, which was offered by Mr. H. H. Warner, the well known Safe Remedies Manufacturer of Rochester, N. Y. This is the only comet prize ever tendered in this country. Very thoroughly has the sky been searched by aspirants for the tempting prize, as well as for the honors of discovery. Three of the discovers, having conformed to the conditions governing the award, have been paid, as follows: Schaeberle $200, Barnard, $200, and Swift $200 twice. The following is a list of the comets of the year, in the order of their discovery: Comet A, Swift, Rochester, N. Y. Comet B, Tobbott, South Africa. Comet C, Schaeberle, Ann Arbor, Mich. Comet D, Encke's (periodic and expected). Comet E, Barnard, Nashville. Comet F, Brooks, Phelps, N. Y. Comet G, Swift, Rochester N. Y. Comet A was found May 1 in Andromeda. It was a faint object, and moving rapidly southeast was soon lost in the morning twilight, and was not seen in the southern hemisphere, no astronomer there having been apprised, in telegraph, of its discovery, as was at first thought advisable. Comet "B" of the sensational one of the year, was the brightest since the memorable one of 1861, and, curiously enough, both were discovered by the same person, this with the naked eye on May 21. Its path was nearly due north, and by its proximity to the sun was soon rendered invisible from any part of the world. It passed the sun only eight degrees west, at noon on June 17, and was first seen in the northern hemisphere on the morning of June 22, its tail only being then visible. The next morning it became an object of general observation, striking every beholder with astonishment. Its subsequent career is too well remembered to need a description here. Its orbit is probably elliptical, having a period of about 3,000 years. From a similarity of elements it was at first thought to be the comet of 1807, but that it is not, now commands the ascent of astronomers. It is still faintly visible in the constellation Cepherus. Comet C, was first seen on the morning of July 18, and somewhat singularly, in almost the same place where comet B had so suddenly appeared after being lost sight of in the southern hemisphere. This would have been pronounced a fine comet had not its immediate predecessor outrivalled it so greatly. Like "B" it had two tails, its elements are unlike those of any comet heretofore observed. Comet D (Encke's,) which has a period of only about 33-40 years, has just paid us another, and the twenty-ninth visit, since it was first detected in 1786. Comet E was discovered on August 18th by Mr. E. E. Barnard. To him belongs the distinction of having been the first in the Southern States to discover a comet. It moves in a parabolic orbit, and, therefore, visited our system for the first and last time. Only those comets moving in elliptic orbits can come to our system more than once. Comet F was first detected on the morning of October 4th, by Mr. W. R. Brooks, and, on the next morning, by Mr. W. F. Denning, of Bristol, England, who immediately announced it which Mr. Brooks for two days delayed to do, as clouds prevented him from determining whether it were a comet of a nebula. It is, notwithstanding that it was visible only through the telescope, by far the most important one of the year. It is a periodic comet of the short period of eight years. It is therefore, and probably for years has been, a permanent member of our system. Comet G, discovered by Swift on the evening of November 16th, is of fair size, though faint, and, like A, E, and F, without a tail. Its elements are somewhat like those of comet A, 1792, but this resemblance cannot be determined until after further observation. It will be seen for some time yet, as the directions of motion southwest will give it a long visible path. An annular eclipse of the sun took place on November 20th, but its annular phase was probably seen by no human being, as its track lay in the south polar regions. Two other eclipses have occurred, but they were only partial, and possessed little scientific value. Comet B was successfully photographed by several astronomers-notably, by Professor Henry Draper, a feat never before accomplished. Several small stars were shown on the negative shining through the tail, though their light passed through probably 101,000 miles of cometic matter. This shows the exceeding transparency of these anomolous bodies. It fact it is one of their distinguished characteristics. What has been learned about comets? Very little. Comet B was the brightest that has appeared since the invention of the spectroscope, and being so exceptionally well placed for observation and spectroscopic analysis of its nucleus, coma and tail, promised much to science. Nothing, however, was observed but the usual spectra revealed by fainter comets. Aside from the apparition of the above comets, no astronomical events of very great scientific value have ocurred. The most notable were the total eclipse of the moon on the evening of June 11th, and the transit of Mercury across the sun's face on November 7th. It was generally invisible east of the Mississippi, but in the extreme Western States and Territories some valuable observation were made by parties especially equipped for this work. An important addition to our knowledge of solar physics, and one destined to have an important bearing on meteorology, has been made by Professor Langley from the top of Mount Whitney, 15,000 feet above the sea. He has proved to his satisfaction that the solar constant of heat, as estimated by Sir John Herschel, Pouillet, Wolhston and others, is very much greater than they supposed. From the top of this mountain, amid the snow and ice, so rare and pure was the air that water was boiled by the direct unconcentrated rays of the sun. Physicists will await with much anxiety his complete report, which will be published by the government. Rochester, N. Y., Dec. 24, 1881. Lewis Swift, Director Warner Observatory |