of these stars has been determined at "all the principal observatories," to use Dr. Gill's phrase, who apparently grew tired of enumerating all the institutions to which he is indebted for the completeness of this section of the work. The final value of the coordinates has been made the subject of a discussion by Prof. Auwers, which may well form a model for similar inquiries, and will be carefully studied by the professional astronomer engaged in similar work. Into minute details which arise in this section, as well as in the use and reduction of the heliometer measures themselves, it is impossible to enter here with sufficient fullness to make the involved process at all clear. The whole interest centres in the nicety with which small residuals are treated. For a similar reason it would be impertinent to offer any criticism which would imply that we have given to the volume the same anxious study and consideration which the combined authors have devoted to their subject. Dr. Gill has supported himself by the ablest authorities in meridional astronomy, his own experience with the heliometer to which he has devoted years of study in perfecting the mechanical arrangements and details is profound, and we have no doubt that we have here all that can be effected by sagacity and experience in deriving the best results from observations which are as perfect as we yet know how to make them. The final outcome of the observations which, in their main intention, were devoted to deriving the value of the solar parallax may be thus presented.

the nutation, it is necessary to assume the luni solar precession. The value adopted is 50" 367 ± 0′′004, but the source from which it is obtained is not very clearly stated, neither is the epoch to which it refers. Apparently it is taken from Newcomb's discussion in the Astronomical Journal, No. 359; but in that paper we have not been able to find this particular value, nor the probable error with which it is accompanied. With this value of the precession, however, and the exact amount is immaterial for this purpose, the constant of nutation is 9" 2068, and pursuing the same line of inquiry the conC- A

stant, C (employing the ordinary notation), is 00032825. Adopting Clark's value for the equatorial radius of the earth, the aberration constant is found to be 20" 4670"012. Here as elsewhere the most probable value of the solar parallax is assumed 8" 802.

The remaining volume, which contains the southern "Durchmusterung," between the limits -18° to -37 declination, is in its way quite as remarkable as the two volumes which we have been considering. Herein we have the first-fruits of the application of photography to the determination of star positions on a large scale. The old and the new methods are brought sharply into contrast. One would naturally like to institute a comparison between the time necessary for the production of these

zones, and that required for similar work, either at Bonn or Cordova. But such a comparison is not easy, nor probably would it be fair. The plates that were taken at the Cape were measured at Groningen. Much time must have been lost in correspondence and in settling the details of a new method. Experience had to be acquired in the most suitable methods of measuring with new and untried apparatus. Prof. Kapteyn was necessarily occupied by his University duties, and could only devote his leisure to the preparation of the catalogue--a leisure which he gave unstintingly; and Dr. Gill is to be congratulated on the good fortune that supplied him with so able and willing a coadjutor.

The plates were taken with a rapid rectilinear Dallmeyer lens of six inches aperture and fifty-four inches focus. During the course of the work this lens was repolished, and a portion of the work duplicated with a second lens; but allowing for all interruptions, the work that was begun on April 15, 1885, was finished in December 1890, with the result that the whole sky was photographed from the South Pole to -19° declination. The free area of each plate was five degrees square, more than 600 being required to cover this portion of the heavens once, without any duplication. At first, when plates were rather slow in action, an hour's exposure was given; but this time was subsequently reduced to about thirty minutes. It is instructive to notice that many plates on a first examination had to be rejected, owing to the fainter stars not having impressed themselves on the film, on account of mist, dewing of the objective, or bad definition. "The more thorough examination necessarily made by Prof. Kapteyn in course of measurement, brought to light a good many more plates which it seemed desirable to re-photograph, so that some of the areas have been photographed three, four, and even five times." Such a report will not be very satisfactory reading for those engaged on the "Carte du Ciel."

The measurement was effected in a manner that necessitated very small corrections to the original readings, in order to obtain the approximate star places, referred to the equinox of 1875; indeed, Prof. Kapteyn says that the coordinates read from the instrument might have been entered directly in the catalogue. We can form a tolerably accurate notion of the time occupied in measuring the plates, for it is stated that on good rich plates two assistants could measure 300 to 400 stars in an hour. Probably 200 would represent the average, and since this portion of the catalogue contains 152,598 stars, we have about 750 hours of actual measurement for one complete examination. Such a rapid collection of results needs no comment. The average distribution of the stars throughout the whole area is possibly of greater consequence than the actual number measured. Of course, the number to a square degree varies very much in different parts of the sky. In the sparsest parts, that is, in Galactic Latitude about - 70°, this number falls to 6:28, rather less than in Argelander; but a comparison of mean results with other zones gives the following numbers.

We do not propose in this place to follow Prof. Kapteyn in his discussion of the magnitudes assigned in the work, and his comparison with the visual magnitudes recorded by other observers. The section is very interesting and likely to lead to much discussion, owing to the curious fact disclosed, that while this catalogue is poorer in number of stars in the poor regions of the sky, it is at the same time richer in the rich regions, than is the catalogue of Schönfeld, from which fact Prof. Kapteyn concludes that the stars in the Milky Way are generally more chemically active than the stars in the other regions of the sky. W. E. P.

NOTES.

:-

REFERRING to our inquiry (p. 488) as to disturbances of terrestrial magnetism during January and February, Dr. C. Chree writes from the Kew Observatory as follows:"With the exception of some small movements on the 10th, our magnetic curves were very quiet from January 1 to 14; but thereafter there was a disturbed time, lasting over January 15 to 21. The disturbance was greatest from the 15th to the 18th -when it was well marked-less on the 19th and 20th, and still

less on the 21st. The 22nd and 23rd were very quiet days. The rest of January was quiet generally, with a few small movements. February was quiet up to the 10th, with the exception of some slight movements on the 5th. From February 11 to 16 there was a moderately disturbed time; on the 20th and 21st there were some smaller movements. It was then quiet to the end of the month. Quiet' is, of course, only a relative word; there is seldom a day in which some slight movement, beyond the mere diurnal inequality, is not visible. In the case of the disturbances on January 15-21 and February 11-16, it was rather a case of numerous well-defined oscillations than of sudden comparatively isolated movements of a conspicuous character."

A CONFERENCE of the International Aeronautical Commission opens to-day at Strassburg, and will continue for several days. Among the experiments to be performed during the meeting is the graduation of thermographs down to - 200° C. by means of a jet of liquid air procured by the Linde method. Dr. Herge sell, the president of the conference, will present a report upon the thermometric experiments already referred to in NATURE (p. 470). M. Besançon will send up a balloon of twelve hundred cubic feet capacity, equipped with meteorograms, which it is estimated will attain an altitude of about twenty thousand feet. Several members of the Paris Academy of Sciences have signified their intention to attend the conference.

THE Paris correspondent of the Times reports that at Monday's sitting of the Academy of Sciences the question of the French national time was introduced by M. Bouquet de la Grye, the president of the Paris Geographical Society and a member of the Section of Navigation and Geography. The fact was recalled that on February 24 the Chamber of Deputies passed without discussion and on a show of hands a Bill providing that French national time should be advanced by 9 minutes II seconds, which was tantamount to the adoption of the meridian of Greenwich by France. The Bureau des Longitudes has, however, sent a protest to the Minister of Education, and the protest has been forwarded to the President of the Senate. M. Bouquet de la Grye asked the Academy to refer the whole question to the joint Sections of Astronomy and Navigation to

be reported upon. This motion was supported by M. Janssen and adopted after some explanations from M. Berthelot and M. Bertrand, the two permanent secretaries.

Ir is announced that the Russian Government has decided to adopt the metric system.

A FRENCH ironclad launched a few days ago was christened the Lavoisier.

PROF. J. E. KEELER has been elected director of the Lick

Observatory, in succession to Prof. E. S. Holden.

THE current number of the Proceedings of the Royal Society contains an obituary notice of Pasteur by Prof. Percy Frankland, F.R.S.

MR. A. D. BERRINGTON is on the point of retiring from the post of chief inspector of fisheries and assistant secretary to the Board of Trade. Among the fishery inspectors who preceded Mr. Berrington were Mr. Frank Buckland and Prof. Huxley.

THE Public Buildings Expenses Bill, providing 2,250,000%. for new public buildings in London, passed through Committee of the House of Commons on Tuesday. Included in the expenditure authorised by the Bill is a grant of 800,000l. for buildings in connection with the Science and Art Museum at South Kensington.

A SWEDISH Scientific expedition to Klondike, conducted by Dr. Nordenskiöld, arranged to leave Stockholm on March 23. Dr. Nordenskiöld will be accompanied by Dr. Gunnar Andersson, professor at the Stockholm High School, and four other persons. The expedition is expected to be absent about two years. Immediately after its return the expedition will make known the results, not only in Sweden, but also to scientific societies in other countries.

IT is reported that Herr J. Stadling, who accompanied Herr Andrée's expedition to Spitsbergen in 1896, has been appointed by the Swedish Anthropological and Geographical Society to undertake a search through Siberia in order to make inquiries as to the fate of Herr Andrée's balloon expedition.. For this purpose Herr Stadling has received the Vega stipendium from the Society. He will start with a companion from Stockholm early in April, and the journey will last probably until January next.

A COMMITTEE has been appointed by the Home Secretary to inquire into the extent to which water gas and other gases containing a large proportion of carbon monoxide are being manufactured and used for heating, lighting and other purposes, and the dangers which may attend such manufacture and use. The committee is composed of Lord Belper (chairman), Mr. H. H. Cunynghame, Dr. Parsons, Dr. Haldane, and Prof. Ramsay; with Mr. J. Pedder, of the Home Office, as secretary.

AT the meeting of the Manchester Literary and Philosophical Society on Tuesday, the President presented the Wilde medal for 1898 to Sir Joseph Dalton Hooker, G.C.S.I., F. R.S.; the Dalton medal to Dr. Edward Schunck, F.R.S.; and the Wilde premium for 1898 to Mr. John Butterworth. The Wilde lecture, "On the Physical Basis of Psychical Events," was afterwards delivered by Prof. Michael Foster.

THE British Association Committee of the Ethnographical Survey is desirous to obtain the services of qualified observers in numerous parts of the United Kingdom, for the purpose of inquiring into all or any of the following subjects: (1) physical types of the inhabitants; (2) current traditions and beliefs; (3) peculiarities of dialect; (4) monuments and other remains of ancient culture; (5) historical evidence as to continuity of race

an infectious disease due to a specific organism. The author's case rests on three lines of argument. He begins by showing that excessive heat does not produce the disease; stokers, ovencleaners, miners, and iron-workers are exposed to temperatures higher than those of any known climate, without ever contracting the malady. The Assam tea-planters and the closely-shaven Chinese are constantly exposed to the hottest sun, and are equally exempt. Dr. Sambon next discusses the geographical distribution of the disease, and proves that the areas in which it is endemic are strictly defined. It is very common in the lowlying regions of the Eastern United States, between the Appalachians and the Atlantic; it is unknown in Europe; it extends along the Nile Valley, Red Sea, and Persian Gulf; it prevails in the Indo-Gangetic alluvial plain, but not on the adjacent Indian highlands. Another peculiar feature of the disease explicable on the infection theory is the occurrence of epidemics, which may decimate hospital wards and not affect men exposed to greater heat and sun. Dr. Sambon concludes that the distribution, etiology, morbid anatomy, and epidemic character of the disease together demonstrate its organic origin. The specific organism has not been detected, but the author believes it lives in the superficial layers of the soil, and is conveyed to the lungs or alimentary canal by dust.

A PRELIMINARY statement just issued by the Canadian Geological Survey, in advance of the detailed annual report, shows that the gold produced by the Dominion in 1897 amounted to a value of 1,238,000/. This means that the Canadian gold output increased by 122'6 per cent. in a single year. In 1896 gold only formed 12.30 per cent. of the total mineral produce of the country (reckoning by value), while coal and building material provided 31'94 per cent. and 15.72 per cent. respect. ively. In 1897 gold rose to the second place on the list, with a percentage of 21'50, coal and building material being credited with percentages of 25°31 and 12'50 respectively.

A SHIP model experiment tank is being built at Washington by the United States Navy, at a cost of about 100,000 dollars. From a description in the New York Engineer, we learn that the tank will be a concrete lined basin, surmounted by a brick building 500 feet long by 50 feet wide, the basin itself being 47 feet long by 43 feet wide by 14 feet deep. On each side of the basin, for its whole length, will be iron rails supporting the ends of a carriage spanning the basin, this carriage being propelled along the tank with the model and measuring dynamometer attached, the model being guided along while still floating freely in the water. The carriage, with all dependent on it, is driven along the tank by four electric motors, taking current from a wire by means of trolley poles. The degree of resistance encountered by the model in passing through the water, also the time taken and the distance traversed, are all

recorded diagrammatically and by electrical means. Hydraulic brake cylinders on each side of the carriage provide for stopping the carriage when run at very high speeds. The models experimented with will be one-twentieth of the actual size of the vessels, the model for a 400-foot ship being thus 20 feet long.

Tests will be made with models for merchant vessels as well as war-ships, and special experiments will be conducted as to the effects of propellers of different sizes and shapes, and the effects of the shape of the after-end of vessels upon the efficiency of the propeller.

MR. J. C. GOUDIE contributes the following interesting observations to the February number of the Victorian Naturalist, the journal and magazine of the Field Naturalists' Club of Victoria :-" A small species of ant, commonly distributed in the Mallee, has a curious habit of keeping in close confinement a rather large mealy aphis, which feeds on the stems of young eucalypts. Round and over these aphides the ants construct a

domed covering of particles of bark, grass, &c., which serves the double purpose of imprisoning the aphides and excluding other ants. Some of these coverings appear to be entirely closed, while others have an opening left in the edge; this doorway is, however, constantly guarded by a pair of ants, which continually move about in the open space, and seem much impressed with the importance of the duty assigned to them. Each enclosure contains generally from three to a dozen aphides, and about the same number of ants. Upon making a breach in some of these structures, for the purpose of observation, I have noticed that many of the 'live stock' were immediately seized by the ants and forcibly removed to a place of safety. The ant under notice is about a quarter of an inch in length, and is of a uniform dark reddish-brown colour, and forms its ordinary habitation under logs, or in old rotten stumps, and sometimes in the ground. Several other species of ants are very assiduous in their attendance on the various aphides, Tetigonidae, and coccids, but the above is the only kind I have noticed that uses such extraordinary means to secure a monopoly of the much-prized 'honey-dew.'”

THE Journal of the Society of Arts for March 4 contains the account of a lecture, by Captain Baden-Powell, on "Kites," in which the advantages and disadvantages of different forms and combinations of kites, as well as their various uses for lifting, traction, reconnoitring, and other practical purposes are fully discussed.

KOENIGS and Lie have proved that if the poles are taken of an arbitrary plane with respect to the conics of a Steiner's surface, their locus is another Steiner's surface. A new proof of this theorem is given by Prof. A. Brambilla, in the Rendiconto of the Naples Academy, who makes use of symbolic notation enabling him to introduce considerable symmetry into the equations.

SOME doubt has existed as to who was the first to discover the microscopic Foraminifera, and to apply the microscope to the investigation of rock-structure. From a communication by Prof. Giovanni Capellini to the Rendiconto of the Bologna Academy, it would appear that on March 3, 1711, a paper, entitled De variis arenis, was communicated to that Academy by Jacopo Bartolomeo Beccari, of Bologna, thus indicating that priority must be awarded to Beccari.

ACCORDING to the views communicated to the Bologna Academy by Prof. Federico Delpino, it would appear that the lesser celandine (Ranunculus Ficaria) of our English hedgerows is to be regarded as the dwarf form of a dimorphic plant, whose dimorphism is of the kind known as gynodiœcism. Prof. Delpino contends that the hermaphrodite form is the larger plant, so common on the Riviera, known as Ficaria calth@folia, and that our Ficaria ranunculoides, Moench, is the smaller female form of the same species. This theory accounts for the facility with which the celandine is propagated agamically, and the sterility of its pollen.

A REPORT on the colour of water by M. Ad. Kemna, of the Antwerp Waterworks Company, has been recently reprinted from the Bulletin de la Société belge de Géologie, and is published by Polleunis and Ceuterick, of Brussels. In it the views of various writers, from Arago downwards, on the physical, chemical, and organic causes of the different colours of different waters, are summarised, M. Spring's theories being dealt with at | considerable length. M. Kemna indicates the practical bearing of these investigations on the testing of water supplies of towns, and describes different methods of applying tests. Of these, the tests known as the Hazen tests, and due to Mr. Allen Hazen, of Massachusetts, find most favour with the author.

ATTENTION has several times been called in NATURE to the various optical illusions by which one of two equal straight lines can be made to look larger than the other by drawing them in particular positions, or a series of parallel lines can be made to look askew by drawing slanting lines across them. A very full and detailed account of these illusions is now given, by Herr Wilhelm Wundt, in a paper reprinted from the Abhandlungen der k. Sächs. Gesellschaft der Wissenschaften, and published by B. G. Teubner in Leipzig. The paper is illustrated by sixty-five woodcuts, showing all the principal and many lessknown appearances of this class, and Herr Wundt discusses at considerable length the causes of these subjective phenomena, whose existence appears to have been first made known by J. Oppel in 1854.

SUNSHINE recorders and their indications are often regarded with suspicion by meteorologists; and not without cause, for it can hardly be claimed that any sunshine recorder in use is a satisfactory physical instrument. In the current number of the Quarterly Journal of the Royal Meteorological Society, Mr. R. H. Curtis reports the results of a comparison between the sunshine records obtained simultaneously from a CampbellStokes burning recorder, and from a Jordan photographic recorder. The comparison indicates that the Campbell-Stokes instrument gives records which can be measured with a fair degree of accuracy by different persons, and are not liable to as much uncertainty as the records of the Jordan instrument. Contrary to the belief of many observers the photographic records were not, upon the whole, in excess of the records obtained with the Campbell-Stokes instrument.

IN the Free Museum of Science and Art (Philadelphia) for December, Dr. Brinton draws attention to a discovery among the ancient marbles of the Louvre of an admirable representation of the wearing of the murmex. It is figure No. 68 in the Salle des Caryatides. The discovery, says Dr. Brinton, removes all doubt of the correctness of his identification of the so-called bow-puller with the murmex. The bow-puller is the name generally given to a bronze object found in museums. The "collections and publications" section of this very useful bulletin is exceedingly good, and we are tempted to hope that our own museums may some day call forth the interest that is evidently felt by Americans in theirs.

THE Reliquary and Illustrated Archeologist for January last is almost entirely anthropological in interest. Mr. Leader Scott's account of the Gallic necropolis in Italy, discovered by Conte Giampieri Carletti on a tract of land at the foot of an indentation of Mount Montefortino, near Arcevia, is particularly interesting; while the next three articles-on some old-fashioned contrivances in Lakeland, by Mr. Swainson Cowper, on the modern use of bone skates, by Mr. Henry Balfour, and on beer and labour tallies, by Mr. Edward Lovett-lead us to the domestic antiquities of our own country, which are all too frequently neglected. The dairy appliances described, inter alia, by Mr. Cowper are very interesting, and we hope he will go on to give us sufficient material to work out the evolution of farm implements.

THE American Anthropologist for November and December last contains a specially good article on the aborigines of Formosa and the Liu-kiu islands, by Mr. Albrecht Wirth. The aborigines who cling to the savage state are short of stature, the majority being under 5 feet 6 inches. They have broad faces with low brows, straight and high noses wide at the nostrils, and lips not so thick even as those of the Malays. The subject of trephining in Mexico is dealt with by Carl Lumholtz and A. Hrdlicka, who give some valuable additional notes upon this interesting subject. Mr. Lewis W. Gunckel analyses the deities of Mayan inscriptions, an obscure subject not perhaps of sufficient interest to attract much general attention.

THE Geologists' Association have arranged an Easter excursion to Bridport and Weymouth, under the direction of Prof. J. F. Blake, Mr. W. H. Hudleston, F.R.S., and Mr. S. S. Buckman. The party will leave Paddington Station on Thursday, April 7, and will return on Tuesday, April 12.

PROF. H. G. SEELEY, F.R.S., will begin the summer course of lecture-excursions with the London Geological Field Class on Saturday, April 23. The subject of the series will be "The Physical Geography and Geology of the Thames and its Tributaries." This is the thirteenth annual course. Mr. R. H. Bentley, 43 Gloucester Road, South Hornsey, N., is the hon. secretary to this class, which provides a systematic course of geological teaching in the open country.

THE Society for the Protection of Birds has issued Part ii. of the Educational Series of leaflets, edited by Mr. H. E. Dresser. Thirteen leaflets are bound up in this part, and each contains interesting notes on the appearance, characteristics and habits of British birds. The information will induce the reader to observe bird-life with a sympathetic eye, and will thus further the Society's objects.

THE second number of the Science Abstracts, issued under the direction of the Institution of Electrical Engineers and the Physical Society, has just been issued. Additions have been made to the list of journals from which papers are abstracted, and it is proposed to considerably enlarge the monthly parts as time goes on. The staff of abstractors is also being increased. The value of Science Abstracts to the physicist and the electrical engineer is very great, and no student of physical science who wishes to keep in touch with the world of investigation can afford to neglect so serviceable a publication.

We have received Natural History Transactions, vol. xiii. part 2, published by the Natural History Society of Northumberland, Durham, and Newcastle-upon-Tyne, an institution which has recently completed its jubilee. The Society promotes an important museum, and detailed enumeration is given of the mammals, birds, and miscellaneous objects to the collections. Prof. G. S. Brady, F.R.S., has a long paper on the British species of Entomostraca belonging to Daphnia and other allied genera. A paper on the "Life History of Coal" seems to take up a great deal of valuable space, and suggests curtailment. There is much interesting information conveyed in the reports of the committees. Lord Armstrong has apparently been a munificent supporter of the Society. We are of opinion, though of course it may not fall in with local necessities, that much of the matter contained in this and similar publications might perhaps be condensed and printed in appendix form, so as to bring the papers and record of actual scientific progress more into prominence. The Proceedings of the Bristol Naturalists' Society, vol. viii. part 2, has also reached us. There are several useful contributions in this nicely-printed publication, covering many branches of science. An interesting paper appears on the "Chemistry of Colliery Explosions," by Mr. Donald Stuart, which is supplemented by a plan of Timsbury Collieries, in Somersetshire, exhibiting the workings traversed by an explosion. Noticeable also is a paper, by Mr. S. S. Buckman and Mr. E. Wilson, on the "Geological Structure of the Upper Portion of Dundry Hill."

THE additions to the Zoological Society's Gardens during the past week include a Herring Gull (Larus argentatus), British, presented by Mrs. Hovell; three Bactrian Camels (Camelus bactrianus, ???) from Central Asia, two Yaks (Poephagus grunniens, ? and juv.) from Tibet, a Beisa Antelope (Oryx beisa, 8) from North-east Africa, a Burchell's Zebra (Equus burchelli, ?) from South Africa, a Weka Rail (Ocydromus australis) from New Zealand, four Radiated Tortoises (Testudo radiata) from Madagascar, a Galapagan Tortoise (Testudo galapagensis) from the Galapagos Islands, deposited.