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are mute so far as real language is concerned. The skull With the Earl of Grey, G.C.M.G., Governor General of capacity has been known to fall as low as 270 cm., but the Canada, as pation, and Sir L. A. Jetté, Lieutenantpresent immature specimens are said to have brains only Governor of Quebec, as honorary president, the fiiteeoth one-seventh the normal size.
International Congress of Americanists will meet IN connection with the third International Colliery Quebec from Monday, September 10, to Saturday, SepExhibition recently held at the Royal Agricultural Hall, a
The work of the congress will have reference representative gathering of delegates from mining and to 41) The native races of America, their origin, geoallied institutions in different parts of the world was graphical distribution, history, physical characters, lanentertained at luncheon by Mr. H. Greville Montgomery, guages, civilisation, mythology, religions, morals and habits. M.P. It was unanimously resolved by the assembly to (2) The indigerous monuments and the archæology of hold an International Mining Conference in connection America. (3) The history of the discovery and European with the fourth International Colliery Exhibition in 1908. occupancy of the New World. The committee of organisaAn organising committee was elected, and among its
tion is as follows:--President: Dr. Robert Bell, F.R.S., members are :-Mr. J. C. Cadman, Prof. S. Herbert Cox, director of the Geological Survey of Canada, Ottawa. Mr. W. Cullen, Prof. Dunstan, F.R.S., Mr. W. B. Esson,
Vice-Presidents : Mgr. J. C. K. Laflamme, Dean of the Prof. W. Gowland, Mr. E. M. Hann, Mr. T. H. Faculty of Arts, Laval University, Quebec ; Hon. R. . Holland, F.R.S., Mr. J. H. Marr, Mr. T. W. Mitchell, Pyne, Minister of Education of the Province of Ontario, Mr. W. H. Patchell, Mr. H. M. Ridge, Mr. W. Rowley, | Toronto ; Dr. D. Boyle, Department of Education, Toronto. and Mr. W. Russell, C.B., with Mr. H. Greville Mont- | General Secretary: Dr. N. E. Dionne, librarian, Legislagomery, M.P., as chairman, and Mr. Allan Greenwell as
tive Assembly. Treasurer : Mr. Alp. Gagnon, Department secretary. All communications should be addressed to the
of Public Works, Quebec. secretary at the offices (provisional) of the conference, In a long and interesting article in the Times of July o 30–31 Furnival Street, Holborn, London, E.C.
on the commercial application of wireless telegraphy, the The committee of bibliography and of astronomical writer deals very fully with the history of wireless telesciences of the Royal Observatory of Belgium has under-graphy and with the various systems now being worked on taken to publish a list of the observatories and astronomers
a commercial basis. The claims of the various systems of the whole world. A request for information, in the
are clearly put forward, and should prove of interest to form of a list of questions, with a model reply relating to
the non-technical readers who are mostly inclined to this the astronomical service the Uccle Observatory, opinion that the words “ wireless telegraphy ” and “ Mar. Belgium, has been addressed to directors of observatories. coni " are synonymous. Among the many systeins which In addition, the list will include such astronomers (uni- have been developed since Mr. Marconi achieved success, versity professors, amateurs, &c.) who are not attached to
may there not be one or more which is entitled to an any observatory, but are nevertheless actively engaged in equal consideration by the authorities? 'This is one of the astronomical research. The information already sent will
chief points raised by the Times correspondent, and it is enable the committee to draw up, not only a list of observ
one which in the interests of the nation should be fully atories, with their geographical coordinates and the recognised. So long as one company is granted a monomembers of the staff, but also a table showing the astro- poly, the cost for commercial use is likely to remain high, nomical activity of the whole world, based upon the in
and any improvements which might be made through fair formation given as to the instruments at the disposal of competition are unlikely to be developed in the same proeach institution, the researches undertaken, and the papers
portion. In Germany a combination of the various systems published. Directors of observatories who have not re
has been made, and any new improvement brought out ceived the question-form, or have not yet forwarded a
is thus welcomed and given the fullest consideration. In reply, as well as unattached astronomers, are requested this manner the highest efficiency is obtained, and if to send the information desired, or to repair any omissions,
some similar arrangement could be arrived at in this as possible to the chairman of the committee,
country it would surely be to the benefit of the country Prof. P. Stroobant, astronomer at the Royal Observatory
at large. As to whether it would be more to the interests of Belgium, Uccle, Belgium.
of the nation for the Government to own and work the THROUGH the death of Prof. H. A. Ward, who was
wireless telegraph stations, when, by a fair trial, the best struck down by a motor car on July 5 in Buffalo, U.S.A.,
system or combinations of systems has been established, a figure well known to every museum and mineral dealer
is a matter which wants the fullest consideration, and in Europe and America has passed away. Prof. Ward
before any further licences are granted to any company was born at Rochester, N.Y., in 1834. For a short period
or companies, this aspect of the situation should be one he assisted Prof. Agassiz at Harvard Scientific School ;
of the first points to be decided by the authorities in in 1855 he went to Paris for a course of study, and travelled
whose charge the welfare of the country is placed. thence widely over Europe ; from 1860 to 1865 he was Prof. HÖNNANN, professor of mining in the Berlin Techprofessor of natural science in Rochester University. From nical High School, died on June 30 in his seventy-first that period until his death, most of his time was spent in year. travelling for the purpose of forming collections of minera
The twenty-third annual congress of the Royal Sanitary logical and geological specimens, which are well known as
Institute was opened at Bristol on Monday under the “Ward's Cabinets." To geological literature Prof. Ward
presidency of Sir Edward Fry, F.R.S. contributed little of importance, but as a collector he did valuable service. He had built up the most complete
PROF. WALTHER LINGELSHEIM, director of the private collection of meteorites in existence; in extending hygiene station in Beuthen, Lipper Silesia, has been apit he spared neither time nor money ; though more than pointed director of the newly founded hygiene instituie seventy years of age, he passed through London last year
in the same town. on his way to cross Europe, searching for new specimens Dr. Wiluelm Bode, departmental director of the Emnwith the ardour of a boy.
peror Frederick Museum in Berlin, has been appointed
Director-General of the Berlin Royal Museums, with the chemist, to take an example, will describe for the botanist rank of Wirklicher Geheimer Oberregierungsrath.
recent advances in chemistry, the botanist will do the. The Berufsgenossenschaft der chemischen Industrie held
same service for the chemist, often, it is hoped, to the its twenty-second ordinary meeting in Detmold on June 28,
advantage and assistance of both." These intentions are, and sanctioned the spending of half a million marks for the
of course, admirable, and the only difficulty to be anticierection of the society's business premises.
pated is in their application. Scientific work is so minutely Dr. Theodor Meyer, whose work on the commercial specialised that the vocabulary common to all investigators
is somewhat limited ; and the greatest trouble the editors preparation of sulphuric acid has given him a high place
will have will be to obtain authoritative articles on subjects among technical chemists, has been appointed director of the installations bureau for the German chemical industry,
of prime importance written in a style that can be read in Berlin, Kurfürstendamm 139, in succession to the late
with ease and interest by the world of science in general, Dr. H. H. Niedenführ.
while at the same time they appeal to the wants of students
of special branches of scientific inquiry. We trust that the Prof. Hugo VON GIlm died in Vienna on June 21, in
new review will be successful in its attempt to provide a his seventy-sixth year. Born in Innsbruck, he studied at
common meeting-ground for men of science, where workers the university under Prof. Hlasiwetz, whose assistant and
in biological and physical sciences can lead one another to co-worker iri several pieces of research in organic chemistry
appreciate the significance of progress made in their respeche subsequently became. From 1863 to 1895 he was first
tive departments of natural knowledge. lecturer, and ultimately professor of chemistry and chemi
We have received a copy of an illustrated prospectus of cal technology in the Vienna Landesoberreal- und höheren
edition of the Systematisches ConchylienGewerbeschule.
Cabinet " of Martini and Chemnitz, now in course of issue Prof. Emil JACOBSEN celebrated his seventieth birthday by Messrs. Bauer and Raspe, of Nürnberg, under the on July 3 in Charlottenburg, where he has lived for
editorship of Dr. W. Kobelt. many years. He was born in Danzig, and studied as a pharmaceutical student in Breslau and Berlin. In 1862
From the University of Wisconsin we have just received
a copy of No. 115 of the Bulletin of that institution bearhe opened an analytical laboratory in Berlin, in which he made a number of valuable observations and discoveries.
ing the date of September, 1905. It is devoted to a review
of the rise and progress of the study of anatomy in the Dr. Jacobson is the originator and editor of several success
United States, drawn up by Prof. C. R. Bardeen, and ful periodicals. From 1862 to 1903 he issued an annual
delivered as an inaugural address on his assumption of publication under the title of the Chemisch-technisches Repertorium, and from 1864 to 1894 the weekly paper
the chair of anatomy in the University. The discourse
includes a reference to the early history of anatomy. In Industrie Blätter, while from 1878 to 1895 he was the director of the Chemische Industrie.
the University of Wisconsin a special department has been
recently established for the study of human and comIn earthquake shock was felt at Manstrae, Alva, and parative anatomy, neurology, histology, and embryology. Blairlogie, in Perthshire, about 3.45 on July 4. The tremor,
Notes on Malayan Pigs " is the title of an illustrated which passed from west to east, lasted about two seconds,
paper by Mr. G. S. Miller forming No. 1466 of the Proand was accompanied by sounds as of distant explosions. ceedings of the U.S. National Museum. As the author has
The annual exhibition of antiquities connected with the had the advantage of studying large series of specimens Institute of Archæology, University of Liverpool, will be in the museums of Washington, London, Berlin, Leyden, held in the Lord Derby Museum, Public Museums, Liver- and Berne, it may be hoped that this communication will pool, from July 11 to July 26 inclusive. The exhibits in- do much towards settling the vexed question as to the clude prehistoric remains from Hierakonpolis; examples number of distinguishable representatives of the genus Sus of provincia! art from Esna, of Hyksos period and later ; inhabiting the Malay area, although it is possible that xarabs, ornaments, and inscriptions from Abydos, of 2000 what Mr. Miller regards as groups
” other naturalists to 1200 B.C. ; pottery and other remains of primitive man,
species.” Several new forms are named. from Kostamneh in Nubia, recently discovered by Mr.
No. 1468 of the Proceedings of the U.S. National John Garstang and Mr. E. Harold Jones.
Museum is devoted to a collection of fishes from Ecuador From the ashes of the monthly magazine of current and Peru, the new forms described by the author, Mr. scientific investigation, Science Progress, which came to an E. C. Starks, including several cat-fishes (Siluridae).' In and in 1898 through lack of support, has arisen a quarterly No. 1476 of the same serial Messrs. Jordan and Snyder peview under the same title, edited, with the assistance of a describe two giant bass from Japan, namely, Stereoly pis strong advisory committee, by Dr. N. H. Alcock and Mr. ischinagi and Erile pis sonifer, both of which have been W. G. Freeman, and published by Mr. John Murray. The long known to science, although imperfectly represented in periodical has much the same appearance as its predecessor,
collections. Despite the fact of both being commonly and the contributions to it are of the same character.
bass,” the two species are referable to distinct There are twelve articles in which methods and results of families. One example of the former was about 6 feet in work in several departments of science are described by length, while a specimen of the latter measured 57 inches, writers actively engaged in scientific investigation. The and other specimens are stated to weigh as much as contributions are thus trustworthy statements of the posi
200lb. tion and progress of important subjects of scientific study, BOTANY is the main subject in the June number of the the biological sciences being given particular attention.
In American Naturalist, the
being entirely devoted the first number the endeavour of the new periodical is to that subject, while Dr. K. M. Wieland discourses at stated to be " to present summaries, as far as possible of a considerable length on the causes of the pressure and flow non-technical character, of important recent work in any of sap in the maple. Osmosis from one living cell to branch of science, to show the progress achieved, and if pos- another is, in Dr. Wieland's opinion, the only vera causa able to indicate something of the line along which further for the latter phenomenon. “Only by flow through the advance is to be made towards the desired end. The cell from one reservoir to another, due to the unequal
osmotic permeability at the two ends, does it seem possible taking an investigation of plants in the Bahama Islands. to obtain pressure by this method. ... The pith-ray cells The collections gathered hitherto by various American seem the only ones in the wood in position to fulfil the botanists have been of a somewhat meagre character, so above requirements. The most probable explanation at that Drs. N. L. Britton and C. F. Millspaugh, with the present is that the pith-ray cells, stimulated by the rising consent of the British botanists concerned, have planned a temperature, become unequally permeable, thus setting up botanical survey of the group. Under the title “ Prænuncia a current and accomp ying pressure from the pith towards Bahamenses, Dr. Millspaugh, in vol. i., No. 3. of the the bark." Two shorter articles, one by Mr. R. C. botanical series of the Publications of the Field Columbian Osburn and the other by Mr. A. S. Pearse, respectively Museum, Chicago,
the orders Amarantacea, deal with the existence of dragon-fly larvæ in brackish Euphorbiacea, Rubiaceæ, and Verbenacce. L’nder the water and with the reactions to chemical and other stimuli Verbenaceæ two new genera, Nashia, allied to Lantana, of the hydroid polyps of the genus Tubularia.
and Pseudocarpidium, allied to Vitex, are founded. The June issue (vol. vii., No. 3) of the Journal of the The systematic articles in the recent part of the Kew Marine Biological Association of the United Kingdom opens Bulletin, No. 4, include a decade of new orchids described with an obituary notice of the late Prof. Weldon, who was by Mr. R. A. Rolle, and a series of " Diagnoses Africanæ " one of the oldest workers at the laboratories, and one of contributed by Mr. N. E. Brown, among which are several the most earnest and enthusiastic supporters of that institu- plants collected by the Hon. Mrs. E. Cecil in Rhodesia tion. This is followed by an illustrated paper on certain and Portuguese East Africa. The nature and uses of British nudibranchiate molluscs. A report is appended on Chinese wood oil, generally known as t’ung oil, are disthe work of the council in connection with the International cussed by Mr. J. M. Hillier, and the tree yielding it is Fishery Investigations. In order to carry out efficiently referred by Mr. Botting Hemsley to Aleurites Fordit. A the work in the North Sea, it was found advisable to number of new species of Indian fungi are recorded by establish a laboratory at
Lowestoft. The experiments Mr. Massee, who also writes a note wherein he advances with marked plaice have proved the occurrence of ex- arguments proving that potato-disease and potato lraftensive migrations on the part of that species. Very curl are more often perpetuated by hibernating mycelium noteworthy are some of the hydrographical results, especi- than by diffusion of spores. ally in relation to the fact that the waters of the North
The exhibit organised by the Meteorological Office for Sea and the English Channel have, respectively, different the International Exhibition, Christchurch, N.Z., 1906-7, origins, according to the season of the year. It would
was, by permission of Dr. Shaw, viewed on July 6 by many appear, for instance, that during the summer and early
persons interested in meteorology. The exhibits autumn of 1903, the Channel waters were largely de
intended to illustrate the methods adopted by the Office and rived from the Irish Sea, while during the remainder
by the institutions associated with it, and the results of the year they were chiefly drawn from the Bay of
obtained on land and sea. For this purpose instruments, Biscay, as indicated by their excessive saltness. The issue published works, and specially prepared diagrams were closes with the report of the working of the laboratory,
arranged according to the branches into which the opera&c., during 1904-5.
tions of the Office are divided. Perhaps the most imposing An important communication on the morphology of fishes display was in connection with maritime meteorology : appears in the June issue of the Quarterly Journal of
many beautiful specimen sheets of monthly charts for the Microscopical Science, in which Mr. E. S. Goodrich dis
various oceans testified to the care and skill bestowed on cusses the development, structure, and origin of the median this important part of the work of the Office. Among the and paired fins. It is shown that the mode of development many objects of interest was a meteorological log contriof the dorsal fins is essentially the same as that of the paired buted by the Prince of Wales when in command of H.M.S. fins, both arising as longitudinal folds, into which grow Thrush. The details connected with the preparation of buds from the myotomes, these being subsequently affected weather forecasts and the issue of storm warnings were by concentration and fusion. The careful and detailed well represented. Among the most attractive charts may observations of the author practically give the death-blow be mentioned one showing the portions of the globe for to the theory that the paired fins of fishes (and con- which daily weather reports are published, with isobaric sequently the limbs of vertebrates generally) are derived lines drawn for December 21, 1905, from the charts from modified gill-arches, for, as is mentioned in the text, received ; maps showing passages of cyclonic depressions that theory gives no explanation of this remarkable struc- across the British Isles and the prevalence of gales on our tural resemblance of the paired to the median fins. On
In the section dealing with climatological statistics such a theory the resemblance is in truth absolutely in- maps were exhibited showing the stations under the control explicable, whereas on the lateral (and median) fold-theory of the English and Scottish Meteorological Societies and such a resemblance is not only easy of explanation, but is the British Rainfall Organisation. Dr. Shaw contributed precisely what we should expect to occur. Mr. Goodrich some carefully drawn diagrams showing the apparent relahas done good service in brushing aside collateral issues tion between the yield of wheat and rainfall; meteoroand putting the crux of the problem plainly before his logical sequences—dry autumn followed by wet spring and readers, and it may be hoped that his efforts will result vice versa--and the meteorological relations of widely disin the general acceptance of the lateral fold-theory. The
tant regions. Although somewhat of a tentative character, contents of the above-named issue of the Quarterly Journal the results were very striking, and led to the conviction of Microscopical Science also include a continuation of Dr. that a great step in the right direction had been made in Woodcock's review of the hæmoflagellates, and a pre- grappling with the multitudinous details at the disposal of liminary account, by Miss R. M. Harrison, of a newly. the Office. The department dealing with automatic record. discovered organ (consisting of a glandular body between ing apparatus took also a prominent position in the exhibit : the fifth and sixth abdominal ganglia) in the cockroach. some excellent drawings were shown illustrating the
Not for the first time American botanists are extending mounting and working of the instruments at the first their sphere of operations to British colonies in under- | order observatories. Among the instruments exhibited by
Date of observation.
some of the principal opticians was a Beckley's anemometer has determined the following radiants of the Perseid with Whipple's improvements, by which the direction of the vane could be read at any time by pressing the electric
No. of meteors
Chief radiant point.
observed. button of an indicator placed in any convenient room in the observer's apartments. Another interesting feature was 1901 Aug. 10
40 some carefully drawn diagrams illustrating the wind circula
+58 tion at the South Pole (results of the Discovery observ
+56 1902 Aug. 10
+60 ations) for each month, both at the surface and in the
35 higher regions of the atmosphere. Mr. Dines exhibited a
Another set of observations made on August 10 and 11, model of a kite and a meteorograph used for the investi
1901, gave 40° + 57° (24 meteors) and 44°+57° (43 meteors) gation of the upper air.
respectively (Astronomische Nachrichten, No. 4098). The Physikalische Zeitschrift for June 15 contains a MAGNITUDE OBSERVATIONS OF Nova AQUILÆ No. 2.description by Prof. Simon, illustrated by plans and photo- The magnitude of Nova Aquilæ No. 2 was observed at graphs, of the new buildings and equipment of the insti- the Bothkamp Observatory on seventy-seven occasions betute for applied clectricity in the University of Göttingen.
tween September 5 and December 10, 1905, and the results A historical sketch is given of the steady development of
are given and discussed in No. 4098 of the Astronomische
Nachrichten. On analysing these results, Dr. Guthnick the teaching of electrotechnics at Göttingen during the
found that the curve showing the diminution of magnitude past twelve years, with particulars of the funds available was not a straight line, but a parabola of the following during this period and of the circumstances which have
form :led to the creation of the new “institute."
m= 10.96 +0.0272t - 0'0000951, An attempt to ascertain the cause of the explosion which
where m=the Nova's magnitude at the time of observasometimes occurs of sealed glass tubes containing radium
tion, 10.96 its magnitude on September 5, 1905, and t the
number of days which elapsed between September and the bromide is described by Mr. Paul L. Mercanton in No. Il time of observation. The departure of the observed values of the Physikalische Zeitschrift. Such an explosion might from those computed, for the same epoch, from the curve possibly be due to the pressure set up within the tube by are given in the table accompanying the results. some gas being gradually produced by the radium. A
AN OBJECTIVE-PRISM COMPARISON SPECTROGRAPH.-In glass tube containing 15 mg. of radium bromide, which No. 5, vol. xxiii., of the Astrophysical Journal, Mr. de had been kept sealed during more than three years, was Lisle Stewart, of the Cincinnati Observatory, proposes a accordingly opened under such conditions as would permit new form of objective-prism spectrograph which might be of the measurement of any increase of pressure, and of the employed for the determination of stellar radial velocities. examination of any gas liberated from the tube. It was
Instead of making two exposures with the one instrument,
as has been proposed in previous suggestions to this end, found, however, that no increase of pressure could be Mr. Stewart proposes to employ two similar spectrographs observed, nor could the presence of helium be detected. mounted rigidly on one equatorial mounting and having The fourth edition of Prof. J. E. V. Boas's “Lehrbuch
the prism bases adjacent. This would bring the two
spectra of each star near together on the plate, and would, der Zoologie für Studierende,” which has just been pub- presumably, eliminate, at least to some extent, the diflished by Mr. Gustav Fischer, Jena, contains much new ferential effects of fexure and temperature changes. matter, both in the text and illustrations. There were 378 | Various details as to the inclination of the two tubes to figures in the first German edition of this work, reviewed
each other, the inclination of the plate, the positions of
auxiliary telescopes, &c., are given in the paper. Prof. in NATURE of January 22, 1891 (vol. xliii., p. 268), and Frost estimates that the probable error of radial velocities this number has now been increased to 577; while both so determined would not be less than 20 km., but Mr. the general and special parts of the text have been Stewart suggests that practical experience would remove thoroughly revised by the author, with the assistance of the outstanding obstacles to more trustworthy determinaProf. J. W. Spengel, professor of zoology at Giessen.
Russian AstroNOMICAL OBSERVATIONS.-We have recently A SECOND edition, revised and enlarged, of Prof. C. Mourru's “ Notions fondamentales de Chimie organique
received five Bulletins of the St. Petersburg Imperial
Academy of Sciences, each of which contains one or more has been published by Messrs. Gauthier-Villars, Paris. papers of astronomical interest. Thus No. 5, vol. xvii. The book is a synopsis of the facts and theories of organic (1902), includes a paper, in French, by Prof. Brédikhine chemistry, and is intended to be an introduction to the on the role of Jupiter in the formation of simple radiants, study of this science.
and in vol. xviii. (1903) MM. Donitch and Jaegermann have articles on the solar envelopes during the last minimum and on the production of comets' tails respectively. Vol.
xix. (1903) contains several astronomical papers, including OUR ASTRONOMICAL COLUMN.
the observations of the chromosphere outside FINLAY'S COMET.-Writing to the editor of the Astrono- eclipses (M. Donitch), and another on comet forms (M. mische Nachrichten (No. 4102), Herr L. Schulhof Jaegermann). Vol. xx. (1904) is largely astronomical, and states that the Jupiter perturbations of Finlay's comet includes articles on the Pulkowa spectrograph, the rebring the time of perihelion passage forward by about pulsive force of the sun, the solar activity, and the Intertwrive hours, thereby making it September 7.5 instead of
national Catalogue ; whilst vol. xxi. (1904) contains papers September 8.0 as given originally. The uncertainty of the by Prof. Belopolsky dealing with radial-velocity problems. elements is probably not greater than a quarter of a day,
A NEW OBSERVATORY for HAMBURG.–From Himmel und so that the perihelion time may now be taken as lying broupon September 7.25 and September 7.75. On Juri
Erde (No. 8, 1906) we learn that a new observatory is this comet was twice as bright as when discovered in 1886,
to be erected near Hamburg. The senate and council of
that town have voted one million marks towards its and its apparent brightness will steadily increase until the end of August; the observation of the comet is, therefore,
erection and equipment. Among the other instruments very probable.
which it is proposed to instal in the new building, the
following are the chief :-A meridian circle of 18 cm. THE. RADIANTS OF THE PERSEID SHOWER.-From a num- (7 inches) aperture, a 60 cm. (23 inches) refractor, a double hoe of observations made at Dorpat during 1901 and 1902, telescope for photographic purposes, and a reflector having M. Wwedenski, under the direction of Prof. Pokrowski, a mirror of i metre diameter.
STAR TRANSITS BY PHOTOGRAPHY." consequently operates as an exposing shutter, permitting
the cone of light from the star to fall for a longer or THE annoyance that arises from the effects of a "magni
tude equation" in transit observations has led to shorter period upon the sensitised plate, the period being various suggestions for its detection or removal. Screens
decided by the contact springs. in front of the object-glass so as to reduce the light of
The sensitive plate when inserted in the dark slide bright stars have been employed with advantage, and
comes within 0.2 mm. of the lines of the reticule, so that various photographic devices arranged with the view of
these lines and the image of the star are practically in the eliminating personal peculiarities have been adopted. But
same focus. Evidently this distance must be made as while ingenuity has been active in proposing practical
small as possible to reduce any error arising from photoapplications and methods, the numerical results have been graphic parallax, but the plate can be shisted in its own few. Recently, Prof. S. Hirayama, of the astronomical
plane, so that five separate exposures can be made upon observatory at Tokyo, has put in practice a contrivance
the same plate. The advantage thus secured of taking similar to that employed by the Rev. Father Hagen in photographing a star in the focus of the transit telescope. In this method the exposure and occultation of a star is alternately effected by means of a bar, moved in obedience to a clock, so as to give rise to a series of dots along the star trail.
The Tokyo transit was for this purpose provided with a triple object-glass, reducing the secondary spectrum, and specially corrected for photographic rays. The aperture was 13.5 cm., and the focal length 211 cm.
Fig. 2.–The bar removed, showing the transit of a star; slightly enlarged. of magnitude to which the telescope was applicable dr. pended, of course, upon the time of exposure permitted by
five stars on the same plate is somewhat discounted by the occulting bar. As a matter of fact, with a full second's the fact that no proper adjustment can be made for deexposure, equatorial stars of the fifth magnitude gave a veloping the plates according to the different actinic measurable image. For stars of greater declination than
intensity of the stars. 73° the exposure of one second was too short to divide The method of observation will be easily apprehended distinctly the successive impressions from each other. The from the description of the apparatus and the character limitations of the method are thus clearly indicated. For
of the results obtained (Fig. 2). The measurement of the fainter stars it seems necessary to consider the possi- plates is not so simple. It is distinctly admitted that to bility of moving the photographic plate at the same rate
a negative is more laborious than to read the as the star, and imprinting on the plate the image of a
fractions of second from chronographic sheet. fixed reticule at known times. The simpler method adopted Theoretically, the beginning of each “break” made by by Prof. Hirayama recommended itself to him, since the the clock is the exact point to which the reading should apparatus could be constructed in the workshops belonging refer ; but owing to the difficulty of measuring the edges to the observatory.
of the dots, due to the want of sharp definition, this plan This apparatus consisted of a camera containing the could not be adopted. The middle of the “break reticule, occulting bar, and the dark slide, which could be
the middle of the “make" has been taken as the full inserted in the place ordinarily occupied by the wires and second. This arrangement, or conventional rule, has probeye-piece. The reticule consists of seven fine lines ruled ably got over the difficulty arising from the photographic upon a microscope cover-glass, firmly cemented to a rect- spread, for it seems not impossible but that the want of angular frame which carries the dark slide. These lines definition at the edges of the dot, or the distance between are interrupted for a short distance in the middle of the two dots, is dependent upon the brightness of the starfield so that they shall not interfere with the star images. But if this source of error is eliminated the author has to The centre of the field is marked by two horizontal wires regret that the length of the dot depends upon the battery, in the ordinary manner. The occulting bar (Fig. 1) is a the spring, the friction, and the moving parts of the
apparatus as affected by the variable component of the force of gravity. “The weakening of the battery has been constantly provided for, but at present I see no way of escape from all the other disadvantages."
This admission seems to deprive this peculiar method of observation of much practical benefit. The question that has to be solved is not so much one of relative accuracy as it is of the possibility of eliminating systematic error, inherent in older and more familiar methods. Looked at as a simple matter of determining the position of a star on a plate at any required moment, the results leave nothing to be desired. In an example worked out in detail it is shown that the error in a single pair of measures is 0.017s., and the mean error of thirty-two pairs, or what may be regarded as equivalent to a complete transit, +0.002s. The results of the measures of 140 stars, made when the plate was moved with, and against, the direction of diurnal motion, gave for the average value of
personal equation +0.0275., the positive sign implying that Fig. 1.-Showing the bar at rest, in the centre of the field.
the time of transit was longer when the plates were
measured along the diurnal motion than when measured thin metal slip about 8 cm. long with a square opening against it. at one end, so as to allow the observer to see the stai
But such measures leave the question of a possible error enter the field, and to permit him to adjust the instrumeni
dependent upon magnitude untouched. Unfortunately, the so that the transit shall take place behind the bar when in
limited range of magnitude and the small number of its stationary position. The end of this bar is soldered to the
observations do not permit any very definite conclusion to armature of an electromagnetic coil. Whenever the electric
be drawn. The author presents a table of forty-six stars circuit is established the bar is lifted up and the star in which the photographic magnitude varies from 1.2 mag. exposed. This circuit is made and broken automatically
to 5.5 mag., and gives residuals for each night and the by contact springs in the standard sidereal clock. The bar
mean residual. The latter is less than 0.055. in all but two 1 “Preliminary Experiments on the Photographic Transit.” By S. cases out of the forty-six. Further, when these mean Hirayama. Annales de l'Observatoire astronomique de Tokyo. Tome iii., residuals are arranged for each star in the order of photo4€ fascicule. (Tokyo, 1905.)
graphic magnitude, no relation between the two is notice