3. The observations by Watson and others afford data for determining the extent of Venus's atmosphere; while the spectroscopic observations indicate that on that planet, as well as on the earth, the atmosphere contains a considerable quantity of aqueous vapor. Prof. Alexander's Hypothesis of the Zodiacal Light. In an interesting "Statement and Exposition of Certain Harmonies of the Solar System," recently published by the Smithsonian Institution, Prof. Stephen Alexander, of Princeton, New Jersey, proposes a new theory of the zodiacal light. This mysterious phenomenon, the explanation of which has perplexed astronomers since the time of Cassini, is regarded by Prof. Alexander as a terrestrial girdle, so situated that its time of revolution around the earth is equal to, and in the same direction with, that of the moon. The author, after stating numerous objections to the commonly accepted hypothesis of a solar ring, and presenting a mathematical exposition of the mode in which the girdle, if a terrestrial appendage, may be sustained, gives the following summary of special coincidences of phenomena with the requirements of his the 3. It accounts for certain periodical changes in form and intensity, etc., of the same, which seem to be completed in a synodical revolution of the moon. 4. It provides for the gegenschein in form and position; and possibly also for "a lunar zodiacal light." 5. It renders a plausible account of the fading, at times, and total disappearance of the zodiacal light. 6. It accounts for the absence of a determinate parallax of the girdle. 7. It shows why, when east and west zodiacal lights are visible at the same time, the middle, even, of the zodiacal arch need not be wholly obscured by the earth's shadow. 8. It provides for the "pulsations." dates of discovery, etc., of those found during the year are as follows: January by M. Paul Henry, of the Paris Observatory. It is a very faint object, little brighter than a star of the thirteenth magnitude. There is a remarkable similarity between the elements of this asteroid and those of the 55th, Alexandra; the comhours, while their inclinations and eccentricities, as puted difference of their periods being only four well as the longitudes of their nodes, are also nearly the same. No. 141, Lumen, was discovered on the 13th of No. 142, Polana, was first seen by Palisa, of Pola, and form of its orbit have not yet been deterAustria, on the 28th of January. The position mined. Its brightness is equal to that of a star of the twelfth magnitude. No. 143, Adria, was discovered at the same place and by the same observer on the 23d of February. This asteroid is also of the twelfth magnitude. Its period, distance, eccentricity, and inclination, are nearly equal to those of Ceres, the first discovered of the group. Nos. 144 and 145, Vibilia and Adeona, were both the 4th of June. The former is of the eleventh, detected by Dr. Peters, at Clinton, New York, on the latter of the twelfth magnitude. The period of Vibilia is 1,509 days; that of Adeona, 1,615. No. 146, Lucina, was first observed by Borelly, at Marseilles, on the 8th of June. It resembles a star of the twelfth magnitude, and has a period of 1,627 days. No. 147, which was named Protogeneia by the discoverer, was first seen by Dr. Schulhof, at Vienna, on the night of July 10th. This minor planet is in the outer section of the zone, its period being over 2,000 days, or about 5 years. Its orbit is very nearly circular, and has an inclination of less than 2° to the ecliptic. No. 148 was discovered at Paris, August 7th, by M. Prosper Henry. This minor planet has the extraordinary inclination of 26°. It resembles a star of the thirteenth magnitude. Nos. 149-157 have not yet been named, nor have their elements been computed. The names of the finders, together with the dates and places of discovery, and also the apparent magnitudes, are as follows: 149... September 21. Perrotin. Asteroids.-At the close of 1874 the number of known asteroids was 140. In 1875 no less than 17 were added to the group, bringing the number up to 157. In the interesting search for these diminutive planets, Dr. C. H. F. Peters, of Hamilton College, New York, is now in advance of all competitors. This distinguished 157... December 1... Borelly... observer has detected 22, while the numbers found by his industrious rivals, Luther and Watson, are 20 and 17 respectively. At the present rate of discovery not only must the list of mythological names be exhausted at an early day, but the labor of calculating the elements and preparing ephemerides must become a serious tax upon the time and energy of computing astronomers. The larger bodies of the cluster have doubtless nearly all been observed, as those recently found are mostly of the twelfth or thirteenth magnitude. It is not improbable, however, in view of recent discoveries, that many more within telescopic reach still remain to be detected. The magnitudes, 222 Comets. The first comet observed in 1875 was that of Encke, detected at Washington by Prof. Holden and Paymaster Tuttle, United States Navy, on the 26th of January. It was also found on the following night by M. Stephan, at Marseilles. An ephemeris of the comet, calculated by Dr. von Asten, had been circulated among astronomers, and the position of the body when first observed was but 15" of arc from its predicted place. When first seen, the comęt's distance from the sun was 142,000,000 miles, and from the earth, 182,000,000. Its appearance was that of an extremely faint nebulosity, less than 2' in di ameter, and without either nucleus or welldefined boundary. The observed acceleration of this comet's motion has generally been ascribed to the resistance of an ethereal medium. This hypothesis, however, has not been confirmed by recent researches. According to Prof. Otto StruveDr. von Asten's calculations show that the last three revolutions of this comet can be perfectly represented by a uniform mean motion, without the hypothesis of a resisting medium, and even with greater precision than all the previous observed returns with that hypothesis. At the same time, during more than one revolution, something like acceleration has been indicated, and nearly to the same amount as Encke had supposed. This was the case between 1862 and 1865. Again, in other revolutions, as between 1845 and 1848, the acceleration has been subjected to very considerable changes. In the actual state of his researches, Dr. von Asten is inclined to conclude that the existence of a resisting medium is not proved by the motion of Encke's comet, and that the observed acceleration in several returns ought to be attributed to the action of other forces; for instance, repulsive power produced by the approach of the comet to the sun, the effect of which might vary considerably, according to the conditions in which the return to the perihelion takes place. Winnecke's comet of short period, which had last been visible in 1869, was detected by M. Borelly, at Marseilles, on the morning of February 2d. This is the third return of this body since the discovery of its periodicity in 1858. It passed its perihelion on the 12th of March. Meteors. At the instance of M. Leverrier, the French Association for the Advancement of Science not long since adopted a systematic plan of observation at the principal meteoric epochs. This plan was attended with marked success on the occasion of the August shower in 1875. At a majority of the observing stations in France the condition of the atmosphere was highly favorable from the 9th to the 11th of the month. At Rouen and Rochefort the Perseids were seen in considerable numbers on the 9th, though the maximum did not occur till the night of the 10th. At Avignon 858 meteors were recorded between 8. 35 P. M. and 3h 40m, A. M. The greatest number, however, was counted at Lisbon, Portugal, where 1,227 were recorded in five hours and twenty-five minutes, commencing at ten o'clock. It seems highly probable, as M. Wolf has remarked, that the August shower is rapidly advancing toward a maximum. The phenomenon will therefore be looked for with more than ordinary interest in 1876. Meteors in unusual numbers-some as bright as stars of the first magnitude-were observed in England on the night of August 5th. Their radiant was near Omicron Andromeda. The Iowa Meteorite of February 12th.-The American Journal of Science, for November, 1875, contains a paper by Prof. N. R. Leonard, on an extraordinary shower of meteoric stones which fell a few miles east of Marengo, Iowa County, Iowa, at about 10 o'clock, on the evening of February 12, 1875. In the States of Missouri and Iowa the meteor was seen throughout a region extending at least 400 miles in length and 250 in breadth. Rev. E. B. Taggart, of Washington, Iowa, describes the body before its explosion as of a "horseshoe shape, greatly elongated; the outer edge very bright, then a narrow dark space, with a cone of intense brilliancy, so vivid as to blind the eyes for a moment. It had not a cometlike train, but a sort of flowing jacket of flame. Detonations were heard, so violent as to shake the earth, and to jar the windows like the shock of an earthquake." The products of the meteor's explosion were scattered over a tract about seven miles long and from two to four miles wide. The fragments varied in weight "from a few ounces to 74 pounds, aggregating, so far as found, 500 pounds weight," of which Prof. Leonard secured more than 300. The specific gravity of the aerolite was found by Prof. J. Lawrence Smith to be 3.57. Diameters of the Planets.-The following values of the apparent diameters of the planets, reduced to the earth's mean distance from the sun, and of their true diameters in English miles, are given in Nature for June 24, 1875: They are founded, in every case, upon the measures which, from observational circumstances, appear to deserve the greatest weight, and in the reduction to true values the solar parallax is taken 8.875, and Clarke's diameter of the earth's equator is adopted. It would, of course, be idle to attempt to offer final numbers, where the difficulties attending observations and the differences between the results of the most experienced and favorably-circumstanced observers are so considerable: In fixing upon the apparent diameters of the bright planets it has been desired to adopt values which shall represent the actual arc values that are presented by the true diameters at the earth's mean distance. Many observations would assign larger values, but undoubtedly less trustworthy for computing real dimensions. Prof. Newcomb's Researches on the Uranian and Neptunian Systems.-The great 26inch telescope of the Naval Observatory, Washington, has been successfully used by Prof. Simon Newcomb in observing the satellites of Uranus and Neptune, and thus obtaining more trustworthy elements of these remote planetary systems. The satellites of Uranus all move in the same plane, and their orbits are very nearly circular. Their dis tances and periods are: The masses of the satellites, according to Prof. Newcomb, are probably less than 100 of that of the planet. Their mutual perturbations must therefore be feeble. The distance of Neptune's satellite from the centre of the primary is found to be 218,550 miles, and its period of revolution, 5.8769 days. No other satellite has been seen, though carefully looked for. The doubtful observation by Lassell in 1850 was therefore probably an illusion. It is a remarkable fact that the orbits of all the satellites of Uranus and Neptune are less eccentric than those of Saturn, Jupiter, and the earth, and that, so far as observations have yet shown, they may be perfect circles. The masses of Uranus and Neptune, obtained by Prof. Newcomb from satellite observations, are too and so respectively. Color of Uranus.-In the monthly notices of the Royal Astronomical Society for March, 1875, Captain W. Noble calls the attention of observers to what he regards as a change of color in the planet Uranus. This astronomer for a number of years had always embodied his impressions as to the color of the planet in the words "a pale-blue disk." The first change observed was on the night of March 9, 1875, when he was "at once struck with the apparent alteration in the character of its light, which was much whiter and brighter than he had ever seen it. "Nay, there was even the faintest suspicion of yellow in it, so thoroughly had every vestige of blueness vanished." As seen through the 26-inch refractor at Washington, the planet, according to Prof. Newcomb, has always presented a seagreen color. Binary Stars.-The elements of the following binary systems have been recently determined; those of the first by Dr. Duner, of the Observatory of Lund, Sweden; those of the others by Dr. W. Doberck, of Markree Observatory, Ireland. We give the periods and eccentricities: Burnham's Sixth Catalogue of New Double Stars. We referred, in our last volume, to the important researches in sidereal astronomy by S. W. Burnham, Esq., of Chicago. In the Astronomisches Nachrichten of November 5, 1875 (No. 2,062), a sixth catalogue, containing ninety new double stars discovered by a 6-inch refractor, is given by the same distinguished observer. No. 21 of this catalogue is a very interesting system. It is known as 3,780 in Herschel's "Cape Observations," where it is described as quintuple, two of the components being of the seventh, and three of the eighth magnitude. Mr. Burnham's examination of these objects, with a view to supply further details, showed the group to consist really of six stars, two of which, on still closer scrutiny, were themselves found to be double, the companions being close and very minute. This remarkable system, consisting of eight members, is just visible to the naked eye as a sixth-magnitude star. It is generally designated as 45 Leporis. Gold Medal of the Royal Astronomical Society.-The council of the Royal Astronomical Society of London, in their annual report of February 12, 1875, awarded the gold medal of the society to Prof. Heinrich L. D'Arrest, Director of the Observatory of Copenhagen, for his observations of nebulæ, contained in his great work "Siderum Nebulosorum Observationes Havniensis," as well as for other important labors and discoveries. In 1851 Prof. D'Arrest discovered the periodic comet which bears his name, and in 1862 he detected the minor planet Freia, the seventy-sixth of the group between Mars and Jupiter. It has been his chief work, however, to determine, with as much accuracy as possible, the positions of nebula discovered by the Herschels, Lord Rosse, and other observers. His labors in this department of research will enable future astronomers to determine the proper motions of those interesting objects, if indeed such motions shall be susceptible of measurement. AUSTRALIA AND POLYNESIA. The area and population of Australia and Polynesia were, according to the latest accounts, as shown in the table on page 55. The principal occupations in Australia are agriculture, stock-raising, and mining. climate, almost throughout the continent, is favorable to the products of the soil. Wheat, maize, barley, oats, and potatoes, are the articles most largely cultivated, while tobacco and sugar also flourish. The vine has of late years been extensively introduced, for winemaking. In New South Wales 454,635 acres of land were under cultivation in 1872, of which wheat, with 177,552 acres, and maize, with 116,745 acres, occupied the larger part. From this land 2,898,463 bushels of wheat and 3,984,958 bushels of maize were obtained. The total number of acres of land occupied was 9,788,728 acres, of which 454,635 acres are under culti vation, 5,134,390 acres are inclosed but not tilled, and 4,199,703 acres are not inclosed. COUNTRIES. Sq. Miles Sq. Miles Popul'tion Populaof Subof of Sub- tion of divisions. Divisions, division Divisions. Total.. 11,672 3,435,102 804,500 1,838,326 acres were wheat, and 122,472 oats. The yield was 3,188,696 bushels of wheat and 2,618,084 of oats. The live-stock statistics of the different colonies are as follows: In New South Wales there were, in 1872, 328,408 horses, 2,287,660 horned cattle, 17,560,048 sheep, and 218,904 hogs. Victoria had on March 31, 1873, 185,796 horses, 222,432 milch-cows, 589,857 other cattle, 10,575,219 sheep, 193,722 hogs, and 122,164 goats. South Australia returned for the same date 82,215 horses, 151,662 cattle, 4,900,687 sheep, 98,436 hogs, and 17,492 goats. The number of live-stock in 1873 in West Australia was-horses, 26,290; cattle, 47,640; sheep, 451,000 748,536; and hogs, 20,948. In Tasmania, in 1873, there were 22,334 horses, 106,308 horned cattle, 1,490,738 sheep, 2,201 goats, and 59,628 hogs. Queensland had, in 1872, 92,798 horses, 1,200,992 cattle, 6,687,907 sheep, and 35,732 hogs. In New Zealand the stock returned at the end of 1871 was 81,028 horses, 436,592 horned cattle, 9,700,626 sheep, and 2,207,000 151,460 hogs. 140,900 4,637,500 In Victoria, in 1873, the extent of inclosed lands was 10,284,439 acres, the area under tillage being 964,996 acres, of which 349,976 acres were devoted to the cultivation of wheat, and 110,991 acres to that of oats, which yielded 4,752,289 bushels of wheat and 1,741,451 bushels of oats. In South Australia the extent of land under cultivation in 1872 was 1,164,846 acres, of which 759,811 acres were devoted to wheat, and 12,609 acres to barley. The total wheat yield in 1872 was 8,735,912 bushels. In 1873, 784,784 acres were under wheat-crop, and the produce was 6,178,816 bushels. In West Australia the returns for the year 1872 show that there were 53,240 acres under crop, of which 31,619 acres were used for wheat. In Tasmania the leading crops are wheat, oats, and barley. Fruit-preserving forms an important branch of industry. The export of jams and preserved fruits in 1873 amounted to 2,263,266 lbs., valued at £61,252. The number of acres under cultivation in 1872 was 324,105, of which 58,610 were wheat, 6,040 barley, and 26,750 oats. The yield of the principal crops for 1873 was as follows: wheat, 947,813 bushels; barley, 124,459 bushels; and oats, 561,247 bushels. In Queensland the total extent of land under crop in 1872 was 62,491 acres. The crops grown were as follows: wheat, 3,842 acres; maize, 21,377 acres; cotton, 12,002 acres; and sugar-cane, 11,757 acres. In New Zealand 1,296,900 acres of land were ander cultivation in 1873. Of these, 131,797 The mineral resources of Australia are also very great. Gold and tin are found in large quantities, while silver, lead, copper, cinnabar, iron, and coal, are also pretty generally found. In New South Wales 9,903,946 ounces of gold, to the value of £38,231,121, had been exported up to December 31, 1871, exclusive of the amount coined in the mint. In 1872, there were exported 186,731 ozs., valued at £731,120, and coin to the amount of £1,656,151. In the same year, 718 tons 12 cwt. of tin were raised, worth £48,832. Diamonds have also been found in considerable number, the estimated number for 1872 being 5,000, the largest weighing 5 carats. In the same year, 1,012,426 tons of coal, of the value of £396,198, were mined, being the product of about twenty-five mines. In Victoria, there had been produced up to December 31, 1873, 43,258,205 ozs. of gold, valued at £173,032,821; 24,719 ozs. of silver, valued at £6,798; tin-ore mined, smelted, and exported, in all £305,886, besides various other metals and minerals. In 1873 the amount of gold was 1,170,397 ozs. In South Australia very little mining is done. The exports of minerals for the year 1872 were-copper, 149,050 tons, valued at £680,714; copper-ore, 26,964 tons, valued at £122,020. In the return for copper-ore, 22 tons of bismuth-ore, valued at £1,168, and 8 tons of spelter are included. The number of mines reported at the close of 1872 was seventy. In West Australia the mineral resources are as yet not fully known. In Tasmania there are large deposits of tin-ore, the yield of which is, however, not yet known. In 1873, 3,920 ozs., of gold, valued at £15,309, were exported. About 10,000 tons of coal were mined in the same year. Queensland, like Victoria and New South Wales, is rich in gold-fields. From 1860 to 1872, 928,198 ozs. of gold, valued at £3,370,626, had been exported. In 1872, 2,427 tons of refined copper, |