the Mare Crisium will be under the terminator, and, on the two following, the Mare Serenitatis will be observable. The Moon is in First Quarter at 3h. 6m. on the afternoon of the 19th, so that the Lunar Appenines and objects in their vicinity may be studied in the evening. Caucasus will be a fine spectacle on the same night, and Tycho will be near the terminator on that of the 21st. Full Moon takes place at 6h. 21m. on the morning of the twenty-seventh day. OCCULTATIONS OF STARS BY THE MOON.-But few of these phenomena will occur in the month of April. Aldebaran will make a near approach to the Moon a few minutes before seven on the evening of the 15th day, but will escape occultation. Two small stars in Taurus, 119 and 120 Tauri, of the 5 and 6th magnitude respectively, will be occulted on the 16th. The disappearance of the former star will take place at 7h. 37m. in the evening; its reappearance at 8h. 26m., very nearly at the same time when the other star will disappear, the reappearance of which will occur at twenty-eight minutes afterwards, or at 8h. 54m. The disappearances will be well seen if the weather be favourable, as they take place at the dark edge of the Moon. The reappearances will be at points in the limb not far from the highest in altitude, and will not be easy to catch.

WINNECKE'S PERIODICAL COMET.-This small comet may possibly become visible during the present month, although its perihelion passage does not occur until the 3rd of July. Our knowledge of its orbit is at present very imperfect, being practically dependent upon the observations made in the year 1858, of which year it was Comet II.,* being discovered by Dr. Winnecke at Bonn on the 8th of March. He remarked that it was nearly 3′ in diameter, very faint and diffused. Shortly after the discovery, it was observed by Drs. Förster and Bruhns at Berlin, Auwers at Göttingen, Luther at Bilk, Rümker at Hamburg, Trettenero at Padua, Schjellerup and d'Arrest at Copenhagen, and Reslhuber at Kremsmünster. When its orbit was computed, it was found that it was extremely probable that it was identical with a comet known as III. 1819, which was discovered by Pons at Marseilles on the 12th of June of that year. Its period being about 5 years, it had passed its perihelion six times between the two observations, but had escaped detection during the whole of that interval. Pons's description of it in 1819

* Comet I. 1858 (discovered by Tuttle on January 4), had also an elliptic orbit, with a period of a little less than fourteen years, but had only been once observed before, in the year 1790.

+ "Astronomische Nachrichten," No. 1133.

was that it was "small, without tail, no perceptible nucleus, the centre of a pretty conspicuous whiteness.*" It was quite telescopic. A conjecture had been put forward by Clausen that this comet was the same as the second comet of the year 1766, the orbit having been considerably changed by its near approaches to the planet Jupiter about the end of 1800, and the beginning of 1812. In 1766, it was for some time visible to the naked eye, and had a tail a few degrees in length. It was first discovered by Father J. Helfenzriede, Professor of Mathematics at Dillingen, in Suabia, on the 1st of April; and was afterwards detected by Messier at Paris on the 8th of April, and observed, on a few days only, by him and Cassini de Thury. After the perihelion passage it was observed at the Cape of Good Hope, and also by La Nux, a councillor at the Isle of Bourbon, a zealous and skilful observer, "who only needed," says Pingré, "good instruments to have made good observations." Good instruments, however, he was unprovided with, and was consequently able only to obtain a series of somewhat rough positions.

Returning to the observations in 1858; Förster, Reslhuber, and Winnecke observed a good series of positions, continuing from immediately after the discovery until the 20th of April. The comet was throughout very faint and diffused, but a little brighter about the middle of April. Reslhuber noticed a very small faint nucleus, situated not quite in the centre of the coma. Watson (now Director of that active establishment) also observed the comet at the Ann Arbor Observatory, Michigan, U.S., on April 4, 5, and 6; also J. Breen, assistant at the Cambridge Observatory, England, on April 18 and 19. It was nearest the earth on the 26th of March, and passed its perihelion on the 3rd of May, on the morning of which day it was observed by Professor G. P. Bond, at Harvard College, Cambridge, U.S.‡

After the perihelion passage it could be seen only in the southern hemisphere, and Professor Moesta, at that time Director of the Observatory of Santiago in Chili, obtained a series of observations, extending from the 26th of May to the 22nd of June.§ On the first of those days, he stated that "the comet has the appearance of an undefined nebula; the light is most intense in the centre, but no true nucleus is perceptible;" but, on the 3rd of June," it exhibits

Berliner Jahrbuch" for 1822, p. 207. "Cométographie," vol. ii., p. 64.

"Astronomische Nachrichten," No. 1149. § Ibid., No. 1184.

a small nucleus, tolerably sharply defined," and, on the 11th, "the comet is well defined by its nucleus."

We may

The comet must have returned to perihelion about the end of the year 1863; but could not be observed at that return. hope that it will be seen at the approaching one, being then very favourably situated for observation. At the beginning of the present month, it will be in the constellation Leo Minor, and on the meridian about ten o'clock at night, with considerable and increasing northern declination; its right ascension being, according to the calculations of Herr Linsser, of the Pulkowa Observatory, about 10h. 30m., and north polar distance about 58°. THE APRIL METEORS.-We are not likely this year to see many of the meteors belonging to this group, since we shall probably be carried through their orbit during daylight. Dr. Galle, at Breslau, saw a considerable number last year on the night of the 19th, and remarked that they began to decrease in number soon after midnight. According to this, the greatest display this year ought to occur at a time corresponding to about that of sunrise in this country, so that it may be worth while to watch a few hours before daylight on the morning of the 20th. It will be recollected that the radiant-point is in the constellation Lyra. The writer has been informed by Mr. Glaisher, that last year several very fine meteors proceeding from the same radiant were observed at Greenwich on the night of the 20th, a little before midnight, after which the sky became cloudy. We would suggest to those who take an interest in the subject of meteoric astronomy to look out in the part of the sky near Lyra for two or three hours before sunrise on both the 20th and 21st. That constellation will be on the meridian at about seven o'clock in the morning.

GENERAL REMARKS.-It is scarcely necessary to remark that the stormy cloudy weather which has characterized the past winter to so exceptional an extent, has been very unfavourable for the prosecution of astronomical observations. We may hope that the present month of April will answer to its name, and open out more inviting opportunities to the votaries of this pre-eminently interesting department of science.

The Sun, the most important body in the system, will probably form one of the most profitable objects of study during this month, which is usually well suited for the continued scrutiny of his disc. All indications show that we are now rapidly approaching a period of maximum of abundance and frequency of the solar spots. And it has already been mentioned in vol. i., p. 145, of THE STUDent,

(for March, 1868), that the most probable length of the interval between two consecutive maxima is just one-ninth of a century or eleven years and one-ninth. This would bring us to another maximum in the course of the year after next (1871), probably about the middle or towards the end of it.

WALLACE ON THE MALAY ARCHIPELAGO.*

SINCE Mr. Wallace's return to this country, six years ago, the work now issued has been looked for with interest by naturalists, ethnologists, and lovers of first-class narratives of travel in strange lands. The preface to the volumes now issued explains the delay, which has been partly occasioned by ill-health, and partly by the enormous mass of material which Mr. Wallace had collected, and required time to study. Three thousand skins of birds, representing about one thousand species; at least twenty thousand beetles and butterflies, of about seven thousand species; besides quadrupeds and landshells-these, indeed, constituted a collection requiring no ordinary amount of labour to arrange, classify, and name; and yet they only formed a portion of the treasures our industrious traveller brought together, and which he reserved for his own use. The total quantity amounted to 125,660 specimens, and few naturalists have been equally successful in discovering new forms, or, what is much more important, in throwing light upon the great question of the origin of species and the tendencies to variation, and the various geographical and geological problems concerning the distribution of life.

Mr. Wallace offers his work to the public as a "mere sketch" of a great subject; but it is the sketch of a master-hand, full of information, suggestion, and thought. Much of it being copied from diaries kept on the spot, it has the freshness that constitutes the charm of good personal narrative, and the author has wisely said most about things and regions least known to former investigators. He divides the Archipelago into five groups of islands-the Indo-Malay Islands (Borneo, Java, etc.); the Timor group; Celebes, with the Sula Islands and Boutan; the Molluccan group (Bouru, etc.); and the Papuan group (the Aru Islands, etc., etc.).

"The Malay Archipelago, the Land of the Orang-utan and the Bird of Paradise : a Narrative of Travel, with Studies of Men and Nature." By Alfred Russell Wallace, author of "Travels on the Amazon and Rio Negro," "Palm Trees of the Amazon," etc. 2 vols. Macmillan and Co.

Mr. Wallace confirms Mr. Earl's division of the Malay Archipelago into an Australian and an Asiatic region, which he names respectively Indo and Austro-Malayan, but he differs from that gentleman in many important points. Borneo, with the islands north and west of it, he places in the first; while Celebes, and eastwards to New Guinea inclusive, is assigned to the second.

The sea which divides Java, Sumatra, and Borneo, "is so shallow that ships can anchor in any part of it, since it rarely exceeds forty fathoms in depth, and if we go as far as the line of a hundred fathoms, we shall include the Phillipine Islands, and Bali, east of Java." The active volcanic character of this district, and the shallowness of the sea, indicate a probability that the subsidence by which that sea was formed is geologically recent, and Mr. Wallace finds their natural history conformable to the notion of the great islands having been connected at no very distant period with the mainland.

"The elephant and tapir of Sumatra and Borneo, and the rhinoceros of Sumatra, and the allied species of Java, and the wild cattle of Borneo, and the kind long supposed to be peculiar to Java, are now all known to inhabit some part or other of Southern Asia." Birds and insects exhibit the same resemblances, and the general conclusion is that the Asiatic continent extended far beyond its present limits at a very recent geological epoch. Mr. Wallace regards the enormous outpourings of matter from the volcanoes of Sumatra and Java as the proximate cause of the depression which has taken place. Celebes and the islands on the East "exhibit almost as close a resemblance to Australia and New Guinea, as the Western Islands do to Asia."

It is very remarkable that the differences in the fauna of these islands seem to have been determined by the geographical and geological changes which isolated them from two distinct regions of mainland, and that the actual state of climate, etc., has had little to do with the matter. Thus, though Borneo and New Guinea are physically alike, they differ widely in a zoological point of view, and "Australia with its dry winds, its stony deserts, and its temperate climate, yet produces birds and quadrupeds, which are closely related to those inhabiting the hot, damp, luxurious forests which everywhere clothe the plains and mountains of New Guinea." Mr. Wallace's residence amongst the Malays and Papuans, led him to the conclusion that they are distinct races, differing radically in physical, mental, and moral characters, and divided approximately