safely imported some years ago, but it is only a few months since that Dr. Caton, after several previous unsuccessful attempts, succeeded in supplementing his gift by transmitting to England an adult female. There is now therefore for the first time some prospect that the Mule Deer may be added to the list of acclimatised species propagating its young in this country. 21. The Chilian Deer (Furcifer chilensis).-The Chilian Deer also belongs to the American group of the Cervidæ, but has some special peculiarities, and together with an allied form-the Andean Deer (Furcifer antisiensis)constitutes a small and distinct section of the American Deer, remarkable for the simple character of the bifurcated antlers. The Chilian Deer is generally known to the natives of Chili as the "Guemul," and, though but slightly deviating from the ordinary deer in general appearance, has been strangely misunderstood by some of the older authors. Molina, in his work (on the Natural History of Chili, classed it as a horse (!) under the name Equus bisuleus, while Hamilton Smith has referred it to the Llamas, and other authors to the Camels! Gay, in his "Fauna Chilena," published in 1847, first gave a clear account of this animal, and figured the female in the accompanying "Atlas," from a specimen in the Museum of Santiago. Gay tells us it is rare in Chili, being only met with in the Cordilleras of the southern provinces. Mr. E. C. Reed, who sent a skin and skull of the "Huemul " for exhibition before the Zoological Society in 1875, tells us that several specimens of it have of late years been procured by the Chilian vessels engaged in exploring the Chonos Archipelago, and that it extends throughout Patagonia down to Sandy Point, in the Straits of Magellan. The Chilian Deer is of about the size of a large roedeer, but much stouter and thicker in its limbs. The antlers of the male, as will be seen by the illustration (Fig. 21), are very simple in character, consisting of a well-developed beam provided with a single anterior snag or brow antler, which curves rapidly upwards, and attains nearly an equal length with the beam itself. The example of this rare deer in the Zoological Society's collection was received from the Jardin d'Acclimatation of Paris in December last, and is believed to be the only individual of the species ever brought alive to Europe. 22. The Radiated Ground-Cuckoo (Carpococcyx radiatus). To the minds of most people the name cuckoo conveys only the idea of a tree-loving bird of strong flight, that utters a well-known cry and drops its eggs in other birds' nests. But the Cuckoo family (Cuculidae) of naturalists is an extensive group, containing many birds which not only have neither cuckoo-like call nor parasitic habits, but differ greatly from our familiar summer visitor both in structure and in manner of life. No better instance can be given of this truth than the very remarkable bird which we now figure (Fig. 23) from an example living in the Zoological Society's "Insect House." Though a "cuckoo" in all the essential points of its conformation, it is a purely terrestrial bird with a pair of long and strong legs, and in its general gait and actions much more nearly resembles a pheasant or a rail than the ordinary cuckoo of this country, with which it claims relationship. The Radiated Ground-Cuckoo was first made known to science in 1832, by Temminck, who described and figured it in one of the livraisons of his "Planches Coloriées," published in that year from a specimen in the Leyden Museum. This, he tells us, was received from M. Diard, a well-known Dutch collector, who had obtained it at the settlement of Pontianak, in Western Borneo. A ticket attached to the foot of the bird called attention to its singular structure and habits, and contained the remark that it differs from the Malkoha Cuckoos (Phænicophai) also found in the same district, in keeping constantly on the ground in search of worms, and in avoiding danger by rapid running, whereas the Malkohas are always met with flying about amongst the trees in search of insects. 1 See Proc. Zool. Soc., 1875, p. 44. Our great countryman, Mr. Wallace, who, we believe, met with this ground-cuckoo in Sarawak, also speaks of its terrestrial habits, and states that its mode of life resembles that of the pheasants of the genus Euplocamus. Little else appears to have been recorded respecting this cuckoo, which is certainly one of the most peculiar forms of bird-life that have of late years been exhibited in the Zoological Society's aviaries. devised by Mr. Stroh. It consists of an iron armature placed between the poles of two double electromagnets, and free to move alternately towards either electromagnet. This to-and-fro motion of the armature is kept up by making and breaking the battery circuit in the coils of the electromagnets alternately. The armature carries a cross-arm or lever-rod fixed at right angles to its axis, and the ends of the rod are attached to two leather diaphragms, which act as partitions across the interior of two boxes. Each of these two boxes communicates with the external air by two pipes or orifices, one on each side of the leather partition. Now when this diaphragm or partition stretching across the box oscillates, air is ex On examining the specimen in question, which, when it first arrived, had only a half-grown tail, but is now in excellent plumage, it will be at once observed that the naked space round the eye has been incorrectly coloured in Temminck's figure of this species. Instead of being of a red colour as there represented, it is of a nearly uni-pelled from one compartment of the box, and at the same form pale green, as is likewise the bill. Few non-professional ornithologists, indeed, would recognise a cuckoo in the pheasant-like ground-loving bird with large bright bill, which is labelled in the Zoological Society's Gardens "The Radiated Ground-Cuckoo." MR. STROH'S VIBRATORY EXPERIMENTS A CENTRE of attraction at the recent Paris Electrical Exhibition was the Norwegian section, in which Prof. Bjerknes of Christiania exhibited his remarkable experiments with little drums or tambours vibrating under water, and attracting or repelling each other according as the phase of the pulsations was like or unlike. An account of his results was published in NATURE, vol. xxiv. p. 361, and the analogy between them and the well-known effects of magnetism was there drawn attention to. The field opened up by Prof. Bjerknes has been entered by Mr. Augustus Stroh, a well-known member of the Society of Telegraph Engineers and of Electricians, who recently delivered a lecture on his researches. Mr. Stroh has gone over the experiments of Dr. Bjerknes in air as a medium for propagating the pulsations of the drums instead of water, and has advanced beyond his predecessor in further experiments on the same line. The beauty of the apparatus and methods devised by him, and the exquisite skill with which he manipulated them, elicited the unanimous admiration of his hearers. The drums employed by Mr. Stroh were small shells of wood having their mouths covered by an elastic membrane and their rears communicating with a flexible pipe, through which the pulsating air was communicated to the membrane, so that it could cause the latter to bulge out or collapse at every wave of air. The source of the vibrations was a vibrating reed, against which the air was forced by a small hand-bellows shaped like an accordion. By employing a flexible forked tube with arms of equal length, each fitted with a drum at the end, the vibratory air-blast from the reed could be conveyed to the drums so as to set them vibrating in like phase; and when one of the drums was mounted on a vertical axis, and free to rotate round it like the pole of a balanced magnetic needle, the approach of the other drum to it resulted in an attraction between them which was very pronounced. In this case the drums were vibrating in like phase, that is to say, they both bulged out and bulged in simultaneously. The mechanical explanation of the attraction is that there is a rarefaction of the air between the drums produced by the simultaneous advance and recession of the membranes toward each other. This rarefaction occasions a difference of pressure between the front and backs of the drums, causing them to move towards each other. When, however, the vibrations are in opposite phase, that is to say, when one drum bulges out while the other bulges in, there is a repulsion between the drums corresponding to a condensation of air in the space between them. This condition of things is ingeniously obtained by means of an electromagnetic air-pump or bellows time air rushes into the other through the orifices provided. It follows that if the orifices communicate with two drums one drum will collapse whilst the other is inflated. Now the oscillations of the armature keep the diaphragm oscillating, and hence the two drums communicating with opposite compartments of the air-chamber are kept vibrating in unlike phase. By employing two such air-boxes or pumps Mr. Stroh is able at a moment's notice to change the vibrations of the two drums from like to opposite phase by simply connecting the drums to the two expelling compartments of the two boxes, or one to an expelling and the other to an indrawing compartment of the box. The same device of a pivoted drum served in this case also to show that when the drums were vibrating in unlike phase there was repulsion between them. In the science of magnetism we are taught that like poles repel and unlike poles attract; but in the experi ments we are considering it is the drums in like phase which attract and those in unlike phase which repel. Mr. Stroh does not attempt to theorise upon his results; but if the analogy with magnetism hold good our ideas of what constitute like poles in a magnet will suffer a considerable change. The aërial analogy for the attraction which always takes place between a piece of soft iron and a magnetic pole, whether it be a north or a south pole, was illustrated by Mr. Stroh in holding quiescent or non-vibrating bodies, such as his hand, or a piece of cardboard, near to either drum. The result was always an attraction of the drum towards the passive surface presented, whatever the phase of the drum. This attraction was prettily shown by means of a small round disk of paper attached to the end of a delicate lever pivoted on an upright stand like a magnetic needle. The dying oscillations of the pole of a magnetic needle, when brought to rest in front of a disturbing magnet, were further illustrated by Mr. Stroh, in presenting the free drum a little apart from the pivoted one, and observing the latter shift round and oscillate before the other, until it came to rest face to face with it. This of course happened when the two drums were vibrating in like phase. When they vibrated in opposite phase, the pivoted drum moved away from the free one, and came to rest further off. Until this point Mr. Stroh had been occupied with repeating Dr. Bjerknes' experiments in air; but beyond this he makes a new departure on his own account. The object of his further experiments was to ascertain what goes on in the air between the vibrating drums; and by inclosing a pair of the drums in an air chamber com municating with a capillary tube containing a column of spirits of wine to act on a pressure guage he showed that when the vibrations were of like phase, the spirit fell, indicating that the air was expelled from between the drums, and on the contrary, when the vibrations were of unlike phase, the spirit rose in the tube, indicating that air had been drawn into the space between the drums, and the pressure thereby raised. The most valuable part of Mr. Stroh's results was now Society and the Fine and Industrial Arts, will be opened at the THE Jubilee Exhibition of the Royal Cornwall Polytechnic Polytechnic Hall, Falmouth, on Tuesday, September 5, 1882. The Exhibition will be on an extensive scale, and the Committee have determined to make it representative of the progress of the past half century in science and art, mining enterprise, naval architecture, and fishing, meteorology, photography, natural history, and statistics, as well as the fine arts pure and applied, more especially in connection with the county of Cornwall. The Exhibition will be attended by men eminent in science, who will come to Falmouth after the British Association Meeting at Southampton, several of whom will deliver lectures at the jubilee. Electricity and the electric light will be a special feature of the Exhibition. The Exhibition itself will occupy the Polytechnic Hall and the Volunteer Drill Hall, and will be open for double the ordinary period. Excursions on a large scale will also be organised for exploring the sea coast, the scientific and archæological interests, and the natural beauties of the neighbourhood. In order to ensure success the Committee with confidence solicit the aid of all Cornishmen. They estimate that 6col, will be required to carry out the object in view. arrived at. By a series of test experiments he demon- programme includes a conversazione on the 15th and various strated that the lines of pressure in the air between the excursions on the 16th. two drums are practically identical in direction with those which Faraday revealed to us in the magnetic field by means of iron filings. These were investigated by exploring the field between the drums with a small taper flame and noting the direction of the blast, as well as with a small windmill mounted on a stand, but the action of both these explorers requires a still atmosphere, and therefore could not be shown to a large audience. Mr. Stroh however, had devised a means of showing the movements of the air by models of the drums vibrating in glycerine traversed by the electric light which threw an image of the drums upon a screen. The membranes of the drums were oscillated in this case by working a crank and pulley, and four star-like water-wheels were pivoted between them in such a manner that when the drums were vibrated the wheels revolved under the streaming of the glycerine caused by the vibrations of the drums. Aniline blue placed in the glycerine at the middle of the surfaces of the drums also indicates the stream lines of the fluid to an audience. Starting from the middle, the glycerine separating into two trails, curved outwards into a kind of volute. This happened at both membranes, so that the space between was filled up by four such curves having a diamond space between them. This effect was produced by unlike phase, and closely resembled the arrangement of lines seen when two like magnetic poles are opposed to each other. On the other hand, the stream lines produced by vibrations in like phase were much less complex, and resembled the lines of force crossing over between two unlike magnetic poles. NOTES Ar a meeting of the subscribers to the Memorial to the late Prof. Rolleston, held at the Royal College of Physicians on Thursday, June I last, it was resolved that the fund subscribed for the above object, which amounts to a little over 1100/, should be paid to the University of Oxford, as trustees, for the purpose of founding a prize, to be known as the Rolleston Prize, to be awarded every two years to the author of the best memoir embodying the results of original research on any branch of the following subjects :-Animal and Vegetable Morphology, Physiology and Pathology, and Anthropology. The prize, which will amount to about 70%. on each occasion, is to be open to all members of the Universities of Oxford and Cambridge who have not exceeded in standing ten years from the date of their matriculation. The adoption of the report of the executive committee was moved by Prof. Acland. Sir James Paget, Mr. Douglas Galton, and other distinguished men of science were present. A vote of thanks to the chairman, Dr. A. B. Shepherd, who has been most active in the furtherance of the objects of the Memorial, and also to the secretaries, Messrs. W. M. Moullin, M.D., C. T. Acland, M.A., A. P. Thomas, M.A., and E. B. Poulton, M.A., was carried. CAPT. DOUGLAS GALTON, R.E., C.B., F. R.S., has accepted the Pre-identship of the forthcoming Congress at Newcastle of the Sanitary Institute of Great Britain. M. DUMAS, Perpetual Secretary of the Academy of Sciences, Paris, has, we understand, requested Dr. Siemens to allow a translation of his paper on the Conservation of Solar Energy to appear under M. Dumas' authority in the Annales de Chimie et Physique. THE Committee for the arrangement of the Electric Exhibition in Vienna have resolved to delay the opening of the Exhibition till 1883. THE fifth annual meeting of the Midland Union of Natural History Societies takes place at Nottingham on June 15. The A YOUNG Finnish lady, Miss Irene Åström, passed the examination for a candidate of philosophy at the University of Helsingfors, on May 24, with great honours. The young lady was subsequently, through a deputation of ladies, presented with a gold watch and chain, at a festive meeting given in her honour at the Esthetic Club, Hesperia. Ar the expense of Herr Oscar Dickson, of Gothenburg, a promising young Swedish entomologist, Herr A. S. Mortenson, will, during the summer, study the entomology of the islands of Gotland and Öland in the Baltic. Το Naturen, that its recent numbers contain an unusually large solstice, when the southern manifestations generally are of rare occurrence, their greatest frequency coinciding with the equinoxes. THE tide of travel, with insects, as with men, seems naturally to be from east to west. With the noted exception of the grape phylloxera and the Colorado potato beetle (as Miss Murthly points out in a paper to the St. Louis Academy), Europe has not received from America any considerable pest, while innumerable noxious species have crossed the Atlantic from Europe. There is a comparative scarcity, too, of Asiatic insect species on the western seaboard of America, notwithstanding frequent ocean traffic. Spite of great arid plains and lofty mountains, nearly all the insects of Eastern American States, including those from Europe, have found their way to the fields, orchards, and vineyards of the Pacific States. One of the latest insect-invaders from Europe is the cabbage or rape-butterfly (Pieris rapæ, Schrank). It appeared about twelve years ago in some northern seaports, and its range now extends from far north in Canada to the south of Georgia. It attacks every cruciferous garden vegetable, but in the flower garden curiously rejects plants of that family in favour of mignonette. Miss Murthly has noted a large amount of premature emergence from the chrysalis, and consequent death; indicating imperfect adjustment of the insect to the climate of its new habitat. In Europe the insect is mainly kept in check by numerous parasites. For several years in America none such came to the aid of the disheartened gardener, but some have now appeared, the most important being a small, metallic green fly, which, though identical with the most destructive European parasite, is proved to be indigenous on both sides of the Atlantic. It lays its eggs in or upon the skin of the mature caterpillar, and from these come small maggots, which live on the fatty tissues of their victim, but do not touch its vital organs till the chrysalis state is reached. THE mines opened a short time since in China in the province of Chihli, with the special support and patronage of Li Hung Chang, have recently become the subject of much adventitious interest in Europe. The working of these mines was wholly a native enterprise; foreign machinery was imported in large quantities, and up to a month or two ago all seemed going on well. A canal between the mines and Tientsin was nearly completed, and it was calculated that 250 tons of fine coal could be forwarded daily to the latter port. Five thousand tons were, it was said, ready at the pit's mouth for conveyance as soon as the canal was opened. It was believed that, with sufficient transport, one thousand tons a day could be raised for many years from the present pits, while it was said that fifty collieries of an equal size to the present one could be opened in or near Kaiping. The information, therefore, telegraphed by Reuter's agent in Shanghai that the further working of the mines had been peremptorily stopped by the Government, came with a shock to many interested in progress in China. It was stated that a censor in a memorial to the throne complained that the long galleries in the mines, and the smoke of the foreign machinery, disturbed the earth dragon, who in his turn disturbed the spirit of the Empress, who died some months ago, and who was buried about a hundred miles off. The irate spirit of the departed lady promptly took vengeance by afflicting the denizens of the palace in Peking with measles. The latter were, the censor is reported to have said, distinctly traceable to the Kaiping mines, which interfered with the feng-shui. The conclusion was obvious: the mines must be stopped. Such was the story told by the Tientsin correspondent of a Shanghai newspaper. The process by which a suggestion that the mines should be stopped grew in the excited minds of the residents of Shanghai into the certainty that they were actually stopped-and thus to Reuter's telegram-is not an unfamiliar one. The latest information from the East enables us to say that the mines are still working as usual, and there is not the slightest evidence that there is or has been any intention of interfering with them. It is even denied that such a memorial as that mentioned above has had any existence except in the imagination of a gobemouche at Tientsin. However this may be, it must be confessed that the petition has a Chinese ring about it, and that the method of argument is one sufficiently familiar to readers of the Peking Gazette. The mines are fortunately within Li Hung Chang's jurisdiction, and while they enjoy his encouragement it is unlikely that fêng-shui or other superstition will be allowed to interfere with them. THE Chinese Customs authorities have, we observed, declined to assist the Chamber of Commerce of Shanghai in making a series of meteorological observations along the coast of China. We have already described the project in these columns. The reason of this refusal is unknown; but it is generally believed that Sir Robert Hart, the Inspector-General of Chinese Customs, intends establishing a special meteorological bureau in connection with his department. If Sir Robert can obtain the assistance of one of the very few men in the East competent for such a task, he may add one more to the many good services which the organisation over which he presides has done to China. A SHARP earthquake shock, at first undulatory, then vertical, lasting seven seconds, was felt at Naples on Tuesday Morning at 6:47. The instruments on Mount Vesuvius gave warning. The centre of the disturbance proves to have been at Isernia, in the Abruzzi, according to the telegrams received since. A conversazione in connection with the Royal Colonial Institute will be held at the South Kensington Museum on the evening of June 23. THE Scientific Publishing Company announce that they have in the press "Photometry and Gas Analysis," by J. T. Brown, F.C.S., divided into three sections-Standards, in two chapters, chapters. The Company also announce the publishing in handy Photometers, in eight chapters, and Gas Analysis, in two form of the "Minutes of Evidence on Electric Lighting Bill, 1882," with text of the bill and a commentary upon the whole. We have received a sensible and interesting lecture on the Relations of Science to Modern Life, by the Rev. Dr. H. C. Potter, delivered before the New York Academy of Sciences; it is published by Putnam and Sons of New York. We have on our table the following books :-British Freshwater Algæ, II., Mr. C. Cooke (Williams and Norgate); Transactions of the Brighton Health Congress (J. Beal and Co., Brighton); Capital and Population, Fredk. B. Hawley (Appleton, New York); Hydrographical Surveying, Capt. W. G. L. Wharton (Murray); Logic for Children, A. J. Ellis, F.R.S. (C. F. Hodgson); First Lessons in Geology, A. S. Packard (Providence, U.S.); Diagrams to First Lessons in Geology, A. S. Packard (Providence, U.S.); Anales de la Officina Meteorologica, vol. ii., B. A. Gould (Buenos Aires); Scientific Transactions of the Royal Dublin Society, vol. ii. series ii.; The Great Diamond Fields of the World, Edw. W. Streeter (Bell and Sons); A Flight to Mexico, J. J. Aubertin (Kegan Paul); Geological Survey of Canada, Report of Progress for 1879-80 (Dawson Brothers, Montreal); New Indian Lepidopterous Insects, F. Moore (Asiatic Society); Regenwaarkemingen in Nederlandsch Indie, 1881 (Batavia); Lohrmann's Mondcharten, J. A. Barth of Leipzig; The Land of the Bey, T. Wemyss Reid (Low and Co.); Catalogue of Fossil Foraminifera in the British Museum; Die Seefischerei an der Westkisten Schwedens, Gerhards. Yhlen (Norstedt und Soner, Stockholm); Botanicon Sinicum, E. Bretschneider (M. D. Trubner and Co.); Tabular View of the Geological Systems, Dr. Clement (Swan Sonnenschein); Report on Injurious Insects, E. A. Omerod (Swan Sonnenschein); Bibliographie Generale de l'Astronomie, vol. ii. (Brussels); Proceedings American Association, 2 parts; Col Jiery Ventilation, Alan Bagot (Kegan Paul); Report U.S. Geographical Surveys, vol. vii. Archæology (Washington); Report of the Metropolitan Board of Works, 1881; Botanical Atlas, parts 1 and 2, D. M‘Alpine (W. and A. K. Johnston); Ancient Water Lines, D. Milne Home (Edinburgh, Douglas); Laboratory Guide, A. H. Church (Van Voorst); Wolf's Naturwissenschaftlich-Mathematisches Vade-Mecum; Madeira, its Scenery and how to see it, Ellen M. Taylor (Stanford); The Foundations of Mechanics, W. F. Browne (Griffin and Co.); Land Nationalisation, A. R. Wallace (Trübner and Co.). THE additions to the Zoological Society's Gardens during the past week include a Rhesus Monkey (Macacus erythraus) from India, presented by Capt. E. B. Stephens, R.N.; a Pig-tailed Monkey (Macacus nemestrinus) from Java, presented by Miss R. M. Stanley; two Striped Hyænas (Hyæna striata) from India, presented by Mr. N. H. Beyts; a Cape Zorilla (Ictonyx zorilla) from Cape Colony, presented by Capt. Farmer, s.s. Pretoria; a Three-striped Paradoxure (Paradoxurus trivirgatus) from India, presented by Mr. R. A. Sterndale; a Puma (Felis concolor) from America, presented by Capt. J. Jellicoe, R.M. s.s. Moselle; an American Tantalus (Tantalus loculator) from Columbia, presented by Mr. H. B. Whitmarsh, R. M. s.s. Moselle; a Java Sparrow (Padda oryzivora) from Java, presented by Miss M. North; a Landrail (Crex pralensis), British, presented by Mr. A. Battiscombe; a White Pelican (Pelecanus onocrotalus) from North Africa, presented by Mr. C. G. Bolau; a Lesser White-nosed Monkey (Cercopithecus petaurista) from West Africa, an Emu (Dromæus novæhollandiæ) from Australia, four Summer Ducks (Aix sponsa) from North America, three Brant Geese (Bernicla brenta), two Common Wigeons (Mareca penelope), a Common Buzzard (Buteo vulgaris), European, deposited; two Great Anteaters (Myrmecophaga jubata) from South America, a Negro Tamarin (Midas ursulus) from Guiana, a Purple Heron (Ardea purpurea) from Java, a B'ue-crowned Hanging Parra. keet (Loriculus galgulus) from Malacca, two Rose-breasted Grosbeaks (Hedymeles ludovicianus) from North America, a Bell's Cinixys (Cinixys belliana) from Angola, purchased; a Red Deer (Cervus elaphus), born in the Gardens; two Herring Gulls (Larus argentatus), two Impeyan Pheasants (Lophophorus impeyanus), four Horned Tragopans (Ceriornis satyra), two Peacock Pheasants (Polyplectron chinquis), bred in the Gardens. The following species of insects have emerged in the Insect House during the past week-Silk Moths: Actias selene, Attacus mylitta, Attacus cynthia, Telea polyphemus; Butterflies: Limenitis sibylla, Argynnis paphia, Lycana iolas; Moths: Charocampa elpenor, Sphinx pinastri, Sesia spheciformis, Sciapteron tabaniforme, Callimorpha dominula. OUR ASTRONOMICAL COLUMN THE COMET (1882 a).—In a circular issued from Lord Crawford's Observatory on May 29, Dr. Copeland remarks that the spectrum of the nucleus of the present comet deserved the closest attention, as it showed "a sharp bright line coincident with D, as well as strong traces of other bright lines, resembling in appearance those seen in the spectra of y Cassiopeia and allied stars." For some weeks the head had exhibited white light, which might be inherent in the comet or the reflected light of the sun; on May 28 the nucleus began to throw out yellow rays, which on June I were also given out by parts of the tail immediately behind the head. Ofy Cassiopeia, Secchi writing in 1877, says: "Le plus remarquable de ces étoiles exceptionelles est y de Cassiopée, qui présente les raies spectrales de l'hydrogène, non pas noires, par renversement, mais directement brillantes, curiosité unique jusqu'ici dans tout le ciel. Il n'y a que 8 de la Lyre qui ait quelquefois les raies brillantes, et encore pas toujours, parce qu'elle est variable"; and he further writes of 8 Lyra, "Elle nous a montré une fois, an maximum d'éclat, les raies brillantes de l'hydrogène, comme y de Cassiopée, chose que nous n'avons plus vue ensuite, bien que nous l'ayons souvent cherchée." The positions given last week for June 10 and II are not likely to require material correction. In seeking for the comet in daylight on those dates, care should be taken to focus accurately (for this purpose Mercury or Venus may be available), and a pretty long "dew-cap" or a cardboard tube should be fitted to take off the direct sunlight from the object-glass. At so short a distance from the sun, it will of course be necessary to use a dark glass, but it may be well that the illumination of the field should not be diminished much beyond that which the eye will readily bear. More than one astronomer considered he had missed seeing the first comet of 1847 in daylight on March 30, by using too dark a glass; this was the opinion of Dawes, who could not otherwise explain his want of success. On August 9 the comet situated near the star 16 Virginis will have the same theoretical intensity of light as at the first Harvard College observations on March 19, setting in London about Ih. 50m. after the sun. On July 5, when not far from Regulus, the intensity of light is equal to that on May 6. THE TRANSIT OF MERCURY, 1881, NOVEMBER 8.-This phenomenon was fully observed at Sydney, by Mr. H. C. Russell and seven assistants. The mean results are as follows, in Sydney, M.T. :— h. m. S. 8 21 57°53 a.m. 8 23 40 65 a.m. 1 40 25.16 p.m. I 42 9°22 p.m. If we calculate with Leverrier's Tables of the Sun and Mercury, and adopt his diameters, the above observations show differences for the internal contacts of +22'95. and +26'2s. respectively. THE SMALL PLANETS.-The number of known members in this group is now 225, the last one having been discovered by Palisa at Vienna on April 19. It appears to belong to the more distant division of the group, the period of revolution exceeding six years. THE CORDOBA ZONES.-We have received vol. ii. of "Resultados del Observatorio Nacional Argentino en Córdoba," containing the observations of stars in zones, made during the year 1872, and shall give an early account of this important work, for which astronomy is indebted to Dr. Gould's untiring energy and zeal, and the enlightened liberality of the Argentine Government in promoting the interests of science. mium. CHEMICAL NOTES IN the Chemical Section of the Meeting of Bohemian Naturalists in Prague, on May 27, B. Brauner (Fellow of The Owens College) communicated a paper on the atomic weight of didyThe author's former determinations gave the number 146.6, but after further purification he finds now didymium to be 145 4. Both samples were entirely free from any known earth metal. Assuming that both numbers are true, the author remarks that the only explanation which can be given, is that "didymium" is a mixture of two (or more) bodies, one, whose atomic weight is smaller than 145'4, and a second, whose atomic weight is greater than 146 6. Thus it is clear that the chemistry of didymium becomes as complicated as that of "erbium," which was thought to be a simple earth, and later on was split up into the following earths, viz. real (1) erbia, (2) terbia, (3) The evidence, scandia, (4) ytterbia, (4) thullia, and (6) holmia. that the mineral cerite contains other earth metals besides cerium, lanthanum, and didymium, has been given by the author some time ago (Monatshefte iii. 1) when he found that the spark-spectrum of the portions intermediate between lanthanum and didymium, as well as of those between didymium and cerium, contains new lines, not belonging to any known cerite metal. The author is pursuing his researches in the laboratories of the Owens College. ZIMMERMAN, who recently determined the densities of gaseous uranium tetrachloride, and bromide, has obtained pure metallic uranium, and made measurements of its specific heat, which completely confirm the number 240 as the atomic weight of this metal (Berichte, 15, 847). |