Imágenes de páginas
PDF
EPUB

Darmstadt, where his father spent his enforced leisure. whom he has trained are his real works on analytical He was apprenticed to the Hof-Apotheker in Darmstadt, chemistry; but others can learn much of his method from and in due time passed his “Gehülfe Examen” with dis- his admirable treatise on qualitative analysis. tinction. He had access to a good collection of books on

A. C. B. chemistry and physics, which he eagerly read. He went as Gehülse to Mühlhausen in Alsace, where he spent several years, and returning to Darmstadt passed the

SERENO WATSON. "Staats Examen" in pharmacy, passing in the first class. But the attraction of pure chemistry prevailed, and in THE

HE last American mail brought the sad intelligence 1857 he went to Heidelberg. Bunsen soon saw what

of the death of this indefatigable botanist, upon kind of student he had got, and appointed him assistant whom, in one sense, the mantle of Asa Gray fell barely in the laboratory. There he met Sir Henry Roscoe, who four years ago. Early in the year he was seized with a invited him to Manchester as his private assistant.' On bad attack of grippe, and although he rallied and was Roscoe's appointment as Professor of Chemistry in the

better for a time, he never recovered strength, and finally Owens College, Dittmar went with him as assistant. In

succumbed on the 9th inst., in the sixtysixth year of his 1861 he became chief assistant in the Edinburgh Uni- age. Of his early life we know nothing, but he appears versity Chemical Laboratory under Prof. Sir Lyon Play about the period that he was appointed Herbarium

to bave published no botanical work previous to 1873, fair. In 1869 he went to Bonn, where he acted first as Privatdocent and afterwards as Lecturer on Meteorology Assistant to Dr, A. Gray at Harvard. From that date, at the Agricultural College at Poppelsdorf. In 1872 he however, onward until within a few months of his death, declined the Chair of Chemistry in the Polytechnic he was, next 10 Gray, the most active writer on North School at Cassel, preferring to return to Edinburgh to his American Phanerogams. Much of his work appeared old post in the University. Here he remained only a

originally in the Proceedings of the American Academy few months, accepting in 1873 the Lectureship’on of Arts and Sciences, under the title of “ Contribution's Practical and Technical Chemistry in the Owens College.

to American Botany," numbered consecutively, the last Thence he removed to Glasgow to succeed Prof. Thorpe being the eighteenth. These consist principally of in the Chair of Chemistry in the Andersonian College. monographs of North American genera and descriptions This office he held till his death, February 9, 1892. He

of novelties. He was also the principal author of died literally in harness. He lectured in the morning, the “ Botany of California,” the last volume of which but not feeling very well, went home in the middle of the appeared in 1880; and since the death of Dr. A. day, and after a few hours’ illness died at 11.30.

Gray, he in conjunction with Prof. J. M. Coulter He was a Fellow of the Royal Society and of the Royal has edited the sixth edition of the deceased author's Society of Edinburgh. In 1887 the University of Edin- valuable " Manual of the Northern United States." burgh conferred on him the degree of Doctor of Laws. This work has been considerably decried by contemThe Philosophical Society of Glasgow awarded him last porary American botanists, because Watson did not inyear the Graham Medal for his investigation into the troduce the changes in nomenclature consequent on a composition of water.

strict and unqualified observance of the law of priority. Dittmar was a man of great intellectual energy, which But in this conservatism he doubtless followed the wishes always took a practical turn, indeed it is rare to see a

of his former master, and enjoyed the sympathies of man so truly scientific in all the operations of his mind

those whose experience teaches them that it is much so free from speculation. Not that his imagination was

easier to make these changes in books than to carry unused, but so prominent before him was the practical them into practice. Watson had a still more important result to be obtained, that it gave a character of reality work, in hand, for he had undertaken the continuation of to the whole process by which he sought to reach it.

Gray's “ Synoptical Flora of North America." How far His most important work was analytical. His great that it will see the light on the same lines as the pub

this is advanced we do not know, but it is not probable investigation into the composition of the specimens of sea-water collected by the Challenger Expedition is a

lished volumes, or as he would have continued it. Unmasterpiece of judgment and skill, important not only for fortunately, an exceedingly useful work, commenced its results, but perhaps even more for its methods. We during the early part of Watson's engagement at Harmay mention also his determination of the atomic weight vard, was never completed. We allude to his “ Biblioof platinum, his method for the analysis of chrome iron graphical Index to North American Botany," which was ore, his examination of the alkaline hydrates and car- only carried to the end of the Polypetalæ. To a great bonates, and the gravimetric determination of the com

extent, Gray's “Synoptical Flora" takes its place, so far position of water. But he did not confine himself to

as the Gamopetalæ are concerned ; but it is difficult to analytical work. He published along with Kekulé à find one's way in the remaining groups. Though Sereno paper on oxymethylbenzoic acid, the first aromatic

Watson was of a retiring disposition, and did not belong alcohol acid ; and also while at Bonn obtained glutaric to the teaching body, nor take a prominent part in the acid by the reduction of Ritthausen's glutanic acid. He gatherings of scientific men, yet the loss of him will be did much excellent work in physical chemistry. We may Member of the Linnean Society of London in 1890, but he

He was elected a Foreign mention the determination of the vapour-pressures of formate of ethyl and acetate of methyl, his work on the

was not a man who craved after honours and distinctions. dissociation of sulphuric acid and on the relation of the composition of acids of constant boiling-point to the pressure under which they are distilled. He made the

NOTES. construction of the balance a subject of special study, It seems almost incredible that the Treasury should think of and the balances constructed for him by Oertling and by stopping the publication of the K’ew Bulletin simply because it Staudinger are models of convenience and accuracy. But Dittmar was greatest as a teacher. Patient and

does not quite pay its own expenses. The periodical, as our careful, he helped his students where they needed help, readers know, is one of high value

, both from the scientific and led them io think and work for themselves. He had and the industrial point of view, and, if the Treasury persists in no ambition to make his pupils analyzing machines; they the design attributed to it, something ought soon to be said on had to understand all that they did. Gradually his great the subject in Parliament by the scientific members. The Times power as a teacher came to be appreciated, and latterly has argued strongly against the proposed step, and the view it his laboratory was filled with enthusiastic pupils. Those has expressed will be shared by all who are capable of forming

an intelligent opinion on the subject. It cannot be expected logical structure of the Western Alps. He will start for Brin. that a very large number of copies of the Bulletin will be sold, disi on April 10, taking with him two Tyrol guides. The as it is really more useful to our colonial Governments than to expedition will last six months. individuals either here or in the colonies.

The anniversary meeting of the Chemical Society will be The Council of the Royal Society of New South Wales has held on March 30 at 4 p.m. awarded to Mr. W. T. Thiselton-Dyer the Clarke Memorial Medal, in recognition of his distinguished services in the cause

Dr. GEORGE BUCHANAN, F.R.S., who has long been known of botanical science, and especially on account of his labours in

as one of the highest authorities on sanitary science, is about to connection with the development and organization of the Bota

erisgn the post of medical officer to the Local Government Board. nical Departments for the Colonies and India, at the Royal The following are some of those who bave consented to serve Gardens, Kew. The medal has been forwarded with a letter, on the jury for the Crystal Palace Electrical Exhibition :-Prof. dated December 23, 1891, in which Mr. W. H. Warren, the W. Grylls Adams, Prof. W. E. Ayrton, Mr. Shelford Bidwell, Honorary Secretary, says :—“The Council fully appreciates Prof. W. Crookes, Major-General Festing, Prof. George Forbes, the beneficial effects which this colony (in common with the Captain Sir Douglas Galton, Dr. J. H. Gladstone, Prof. D. E. other British possessions) has already derived and will continue Hughes, Mr. W. H. Preece, Prof. Silvanus Thompson. to derive from the foresight and scientific zeal you have displayed in the building up of the Colonial Departments of your institu- On Monday evening Mr. Kimber asked the Chancellor of tion; the Council is also aware of the assistance which the the Exchequer why the British Government had not concurred Department under your direction has given to institutions in with the other European Governments in joining the InterSydney, and is not unmindful of the fact that the first collections national Geodetic Bureau of Vienna. In reply, Mr. Goschen obtained by the Sydney Technological Museum were received said the question of joining the reconstituted International from the Museum of the Royal Gardens, Kew. The Council | Geodetic Bureau was raised just five years ago, the condition trusts that you will therefore accept the medal, as a token on being an annual contribution of 2250f. a year for ten years, the part of this Society of the appreciation in which your work besides the expense of sending delegates to attend the meetings is held in Australia.” Mr. Warren's letter, with Mr. Thiselton.

of the Bureau. “Our experience of the International Metric Dyer's answer, is published in the new number of the Kew Bureau at that time,” Mr. Goschen continued, “showed that Bulletin. In a presatory note the Director of the Royal the expenditure upon such undertakings tends to increase out of Gardens explains that in publishing the correspondence he feels proportion to their actual utility, and it was considered that the "he is only putting on record a mark of appreciation as hand practical advantages of joining the Geodetic Bureau were not some as it is spontaneous, on the part of one of the most dis- sufficient to justify the guaranteeing of the sum named. So far tinguished of the colonies of the Crown, of the usefulness of as I am aware, the question has not been mooted since." the official work which the Kew establishment could alone accomplish with the continuous and loyal assistance of every

The first annual meeting of the North-West of England

Boulder Committee was held at the Technical School, Stockmember of its staff.”

port, on the 19th inst. The year's work has been einineni lv STUDENTS of archæology will be glad to hear that Mr. F. C. practical and useful. The Committee, in addition to contributing Penrose has gone to Greece to carry on his investigation of the a very large portion of the Report of the Erratic Block Commitdates of Greek temples as derived from their orientation. He tee of the British Association presented at Cardiff, have read hopes to determine the orientation of many foundations not and discussed more than forty papers and reports at their included in the list given in his recent paper on the subject. monthly meetings; these they now propose to print indeIle will also verify, as far as possible, the approximate results at pendently. Maps on the one-inch and six-inch scale have been which he has already arrived.

acquired, partly by purchase and partly by presentation, includ

ing a valuable set from Sir A. Geikie, F.R.S., Director General On March 28 many educational institutions in Austria and of the Geological Survey. On these good progress has been Germany will celebrate the three hundredth anniversary of the made, by a distinctive system of symbols, in showing the position birth of Johann Amos Comenius, one of the most illustrious of and origin of the boulders over a large area. A thoroughly pedagogues. The Austrian Government, however, has for

practical “Drift Primer” has been drawn up by the Secrebidden the proposed celebration in Bohemia. Comenius was

tary and approved by the Council of the Committee for by birth a Moravian. He anticipated many of the best ideas the instruction of observers, and has circulated beyond of our own time on education, and by his numerous writings the limits of the Committee. Boulder-forming rocks have and his great personal influence produced a profound impression been collected in England and Scotland, for reference puron his contemporaries. Charles I. invited him to England to

poses, and the nucleus of a Glacial Drist library formed. The improve the organization of English schools ; but the outbreak Annual Report shows a large increase of members outside the of the Civil War made it impossible for him to give effect to his original district of observation, and it was therefore decided ideas in this country.

that henceforth the title should be altered to “The Glacialists' Prof. GRIESBACH lately forwarded to Vienna various fossils

Association,” and that the rules be altered so as to include the which he had collected during his geological explorations in the

whole of "the British Isles." The President, Mr. De Rance, Central Himalayas on behalf of the Government of India. They

and the Secretary, Mr. Percy Kendall, were re-elected, and resemble so closely fossils found in corresponding Alpine strata,

the following Vice-Presidents were elected : Vice-Chancellor that they have excited much interest ; and the Royal Imperial Kay, and Dr. Ricketts, and a Council of fifteen.

Sir Henry Bristowe, Mr. Brockbank, Mr. Gray, Alderman Academy of Science, Vienna, has determined, with the cooperation of the Indian Government, to send an exploring AMONG the contents of the new number of the Kew Bulletin party to the Central Himalayas to compare their geological is an interesting account of the Spanish Broom as a fibre plant. features with those of the Eastern Alps. The leader of the Some time ago a French scientific journal printed a notice respectparty will be Dr. Carl Diener, lecturer on geology at the Uni- ing the use of the fibre of the Spanish Broom among the peasants versity of Vienna. Dr. Diener is President of the Vienna Alpine in the neighbourhood of Lodéve, and in the remote hamlets in the Club, and is well known as the author of a work on the geo- ! mountains of Languedoc. An effort was made to secure speci

ܪ

mens of the fibre, and of articles produced from it, for the col. twelve of these months have been carefully examined, and show lections in the Museums of Economic Botany at Kew. It was no less than 264 depressions in various parts of the ocean. Of with the utmost difficulty that specimens were obtained; but these, out of 62 which originated south of 40° N., only 16 had ample material for arriving at a definite conclusion with regard sufficient energy in them to cross the meridian of Greenwich, to the origin and character of “Genista fibre” was at last while out of 22 which originated further south only II received. There is now in the Kew Museums a complete set, crossed the Atlantic, and these were not all felt as actual storms consisting of twigs, fibre in various stages of preparation, as well in this country. The practical outcome of obtaining telegrams as yarns and coarse cloths. These were sent hy Mr. Consul from America has not been satisfactory, but this failure has Perceval. There is also a sample of coarse sheeting received probably been mainly due to the fact that the reports " have from M. Geoffroy St. Hilaire through the English Embassy been neither numerous nor full enough.” This accurately reat Paris. These fully illustrate the fibre industry connected presents the case at the present time ; but we hope it is not too with Spartium (Genista) junceum. “ It is evident,” says the much to expect that, with our present knowledge of the paths Bulletin, that this interesting rural industry is fast dying out taken by depressions with regard to areas of high pressure, some in France. It may be said to exist now only in very remote further advance may shortly be made in predicting storms by hamlets in the Cevennes. The inquiries made by Kew were means of more numerous and suller telegraphic reports both therefore only just in time to secure the last specimens of clothi srom outward and homeward bound ships. made in the laborious fashion before the days of rapid communication and the introduction of cheap cotton and other

The following are among the lecture arrangements at the goods.”

Royal Institution for the period aster Easter :-Prof. T. G.

Bonney, two lectures on “The Sculpturing of Britain—its Later One of the most interesting of recent additions to the Stages” (the Tyndall Lectures); Mr. Frederick E. Ives, two Museums of Economic Botany at Kex has recently been lectures on

· Photography in the Colours of Nature”; Prof. received from Sir John Kirk. It consists of a large sheet of Dewar, four lectures on "The Chemistry of Gases ”; Prof. H. bark cloth prepared by the natives of Uganda from the inner Marshall Ward, three lectures on "Some Modern Discoveries bark of a species of Brachystegia, a small genus of trees belong. in Agricultural and Forest Botany" (illustrated by lantern). ing to the Casalpineæ sub order of the natural order Legu. | The Friday evening meetings will be resumed on April 29, minosa. Various details relating to the use of Brachystegia as when a discourse will be given by Dr. William Huggins on a source of bark cloth are given in the current number of the “ The New Star in Auriga”; succeeding discou' ses will probKew Bulletin. The same number contain: sections on oil palmably be given by Captain Abney, Dr. B. W. Richardson, Mr. fibre and the sources of rubber supply.

J. Wilson Swan, Sir James Crichton-Browne, Mr. Ludwig ANYONE who may desire to devote himself to the study of Mond, Prof. Dewar, and other gentlemen. Finnish archæology and folk-lore will find ample material for A GOOD seam of coal from 7 feet to 8 feet thick has been study in the information collected by the late Dr. H. A. Rein- discovered by Mr. Hughes, of the Indian Geological Survey, on holm. He was chaplain of the prison, and pastor of the Lutheran the banks of the Tenasserim River, which is navigable to that congregation, at the Fortress of Sveaborg, near Helsingfors, point. The Government of India has sanctioned the grant of a and for many years devoted the whole of his leisure time to the

large concession in Mergui to Ah Kwi, a wealthy Chinese resi. amassing and arrangement of facts relating to the life of the

dent of the Straits, to prospect for tin. According to the Finnish people in pist times. He died in 1883. Only a few Calcutla correspondent of the Times, this is the first attempt to results of his researches have been published. By far the greater encourage on a large scale the mining industry in Mergui. part of his work is preserved in manuscript in the Historical

Messrs. CROSBY LOCKWOOD AND Co. have issued the Museum at Helsingfors. An interesting account of the labours of this indefatigable investigator is given in the c!ırrent number

fourth edition of Mr. Primrose McConnell's “Noie-book of of Globus.

Agricultural Facts and Figures for Farmers and Farm

Students.” The author was originally induced to prepare the MR. R. H. Scott delivered a lecture at the Royal United volume by noticing the great value of Molesworth’s “ PocketInstitution on March 18, on a subject of much importance to book of Engineering Formulæ” to engineers, and of similar meteorologists in this country, viz. “Atlantic Weather and its books to those engaged in other professions. It occurred to connection with British Weather.” He pointed out that less him that a book compiled in the same style, and devoted 10 than a quarter of a century ago, before synchronous charts were Carming matters, could not fail to be useful as a ready means of in vogue, it would have been impossible to have traced a storm relerence for resreshing the memory. The success of the “Noteacross America and the Atlantic to our own coasts ; but this can bosk” has proved that he was right. The progress of agrinow be done with considerable certainty. The broad principles cultural practice and science has been so rapid that it has been which govern the weather system of the Atlantic were shown on necessary for him to rewrite the greater part of the hook, and two diagrams exhibiting the mean pressure, and the regions of nearly twice as much matter is given in the present edition as greatest disturbance of temperature, on the globe, in our winter. was contained in the earlier issues. The use of a slightly The latter chart showed that, at that season, the relatively longer page and thinner paper has prevented the size of the warmest district is near Iceland; and the barometer chart volume from being much increased. showed that close to the same region the barometer is lowest. The reasons of these relations, which involve the first principles counties of Scotland has issued its annual report for 1891. It

The Agricultural Research Association for the north-eastern of modern weather knowledge, were fully explained. The more

includes a valuable paper on “Root Hair-,” in which Mr. T. northern part of the Atlantic area interests us the most. The whole region from 40° 10 70° N. is constantly visited by cyclonic Jamieson presents the results of a laborious investigation he has

carried on during the past three years. He also gives some depressions, and in order to throw some light on the origin and

hints on permanent pasture, and brings together various items history of these depressions, and of the storms which they at

of information which are likely to be of immediate benefit to times bring with them, various institutions have published daily

farmers. maps of the weather in the Atlantic. The most complete of these maps were published by the Meteorological Office for If we may judge from its twenty-sixth annual report, the thirteen months, commencing with August 1882. The last American Society for the Prevention of Cruelty to Animals is

doing much good work. During the past year it prosecuted no At the meeting of the Belgian Academy of Sciences fewer than 17,847 cases in the courts. Through its efforts on March 6, Prof. Spring announced that the late Prof. 49, 118 disabled animals were temporarily suspended from work; | Sias had left, in an almost completed condition, a long and 34,264 horses, disabled past recovery, were humanely destroyed; important memoir describing the results of several further 6444 disabled horses were removed from the streets in an stöchiometrical investigations. It is entitled “Silver," and will ambulance. The number of prosecutions and other official forthwith be edited, presumably by Dr. Spring, and published. interferences was larger than in previous years, but it does not It may be remembered tha., after the publication of Prof. Stas's follow that cruelty is more common than it was. The increase classical memoir upon the preparation of absolutely pure silver is due to the greater vigilance of the Society's officers.

and the atomic weight of that metal, doubts were ihrown by

Prof. Dumas on the validity of the work on the ground that the In a paper contributed to the current number of the Journal silver employed was not free from occluded atmospheric gases. of the Franklin Institute, Prof. Lewis M. Haupt argues strongly Moreover, Prof. Dumas expressed doubts as 10 ihe bearing of in favour of the construction of a ship canal between New York the work upon the celebrated hypothesis of Prout, according to and Philadelphia, connecting the Delaware and Raritan Rivers. which the atomic weights of all the other elements are supposed Such a canal would, he maintained, extend the Erie Canal and to be multiples of that of hydrogen. For, if silver possessed its benefits to Philadelphia, and open to its manufacturers over the atomic weight attributed to it by Prof. Stas, the atomic 16,000 miles of waterways in the great basin of the Mississippi. weight of oxygen became 15'96 and not the whole number 16, It would reduce the distance by water to New York harbour and consequenuy Prout's hypothesis in its original form would from 240 to about 60 miles, would afford an inside and safe be negatived. In order to set these doubts at rest, and to leave passage to Eastern, Sound, and Hudson River ports; would his work in a perfected condition, Prof. Sias has prepared a develop a large population along the entire route, and so benefit quantity of silver with such extreme precautions that he has the railroads traversing the district. "In short,” says Prof. succeeded in obtaining it entirely free from occluded gases, and Haupt, “the effect would be to reduce the rate per mile, as well from even the minutest traces of the materials of the vessels as to shorten the distance between the two greatest centres of employed. So persect is the purity of this silver that even when population on the American continent, or, we may say, in the heated to the temperature of the melting-point of iridium not a world; for nowhere else on the globe is it possible by so short trace of sodium can be detected in the spectrum of the vapour. and inexpensive a waterway to connect such large populations with this silver he has repeated his former determinations of and so many and valuable interests."

the atomic weight of the metal, and it is satisfactory to learn The Bethlehem Iron Company, Pennsylvania, is to erect at

that the final number obtained is, as Prof. Stas himself expected the Chicago Exhibition a full-size model of its 125-ton steam

it would be, identical with that formerly obtained. Hence, the hammer, said to be the largest in the world. It will span the objection of Prof. Dumas cannot longer be entertained, and main avenue of Machinery Hall

, and will rise to a height of the atomic weight of oxygen would indeed appear to be 15'96 90 seer. At the last Paris Exhibition great attention was

and not 16, for the numbers obtained by Prof. Stas agree so attracted by a similar model shown by the Creusot works, but remarkably that an error of four-hundredths of a unit would representing only a 100-ton hammer.

apparently be out of the question. In addition to this im

portant memoir, Prof. Stas has also left the data of a series of BARON VON MUELLER records, in the Victorian Naturalist iwelve separate determinations of the stochiometric relation of for February, that, while elaborating diagnoses of new Papuan silver to potassium chloride, the materials for which were the plants, he was pleasantly surprised to find among the novelties pure silver just described, and a specimen of potassium chloride, an Antholoma. This genus has hitherto been supposed to be also prepared with a care and precaution quite in keeping with restricted to New Caledonia. The Papuan species is dedicated the rest of the work of the great analyst. The results of these to Prof. van Tieghem. The denticulation of the leaves, the determinations are described by Prof. Spring ai agreeing in a elongation of the setule of the anthers and the three-celled most wonderful manner, and will afford another valuable base to ovulary already separate A. Tieghemi from A. montanum. which the atomic weights of many other elements may be reAmong the novelties are also Oxalis (Biophytum) albiflora, ferred. Besides these two memoirs, a third is mentioned by Sloanea Forbesii, which approaches S. quadrivalis in many Prof. Spring, relating to the spectra of several metals which Prof. respects, but is petaliserous, and Quintinia Macgregori is Stas has obtained in the purest state in which these metals have particularly remarkable.

ever probably been seen. The whole of these memoirs, conA “Treatise on Physical Optics," by Mr. A. B. Basset, sisting of about tilteen hundred pages of manuscript, it is will be issued shortly by Messrs. Deighton, Bell, and Co.

intended to publish forth with in three separate treatises. THE proper title of Mr. A. E. H. Love's work (included in

The additions to the Zoological Society's Gardens during the our list of forthcoming scientific books last week) is " A Treatise past week include a Ring-necked Parrakeet (Palveornis torquatus on the Mathematical Theory of Elasticity."

6) from India, presented by Mr. George H. Whitaker; a Grey.

breasted Parrakeel (Bollorhynchus monachus) from Monte Video, Messrs. NALDER Bros. AND Co. have issued price lists, presented by Miss Mildred Whitaker ; a Roseate Cockatoo carefully illustrated, of their electrical testing and other scientific i (Cacatua roseicapilla) from Australia, presented by Mr. J. S. instruments, and of their ammeters and voltometers, resistance Gibbons ; a Nutmeg Fruit Pigeon (Carpophaga bicolor) from the frames, &c.

Torres Strails, presented by Mrs. Fitzgerald ; iwo Pike (Esox MESSRS. DULAU AND Co. have issued Part xvii. of their lucius) from British Fresh Waters, pre:ented by Mr. P. F. "Catalogue of Zoological and Palæontological Books." It Coggin ; a Manichurian Crane (Grus viridirostris) from North contains lists of works on Mollusca and Molluscoida.

China, deposited. IN Mr. George S. Carr's letter on the terms "centrifugal force" and " force of inertia" (NATURE, P. 463), in the second

OUR ASTRONOMICAL COLUMN. sentence of the second paragraph, read “in every case as the FUZZINESS OF SOME VARIABLE STARS.- Mr. Cuthbert G. reaction to the normal component of the centripetal force” (not Peek has, during the last six years, used his 61-inch achromatic centrifugal").

for the investigation of the light-curves of variable stars. In

this month's Knowledge he describes some observations of clear that the new body was not a hitherto unobserved nebula changes in appearance of a few variable stars at different epochs, to begin with. Three variables-T Cassiopeiæ, R Cassiopeiæ, and S Herculis- The Astronomische Nachrichten, No. 3079, contains (at p. have been frequently observed as (a) remarkably well defined, 109) the following communication from Mr. H. C. Vogel, almost planetary, disks ; (6) well-defined stars, surrounded by a Director of the Astro-physical Observatory at otsdam, dated more or less dense, ruddy atmosphere ; (c) large, woolly, ill. February 29: defined images, resembling a small but bright planetary nebula ; “Although the spectroscopic observations of the Nova in (d) at minimum, in place of the variable, a slight bluish nebu- Auriga are not yet concluded-since the star will probably conlosity. The changes appear to be real, for stars near the tinue visible for some time, I consider it of importance, in the places of the variables have been seen clear and sharp when the interest of the subject, to communicate my observations made haziness of the variables was unmistakable. Other stars with hitherto, and the conclusions drawn therefrom, even though the regard to which Mr. Peek has made similar observations are latter should not in the future be confirmed in all points, S Cassiopeiæ, R Tauri, R Auriga, V Cancri, R Ursæ Majoris, "Concerning, first, the direct spectroscopic observations, I S Ursæ Majoris, R Camelopardi, R Bootis, S Coronæ, R have, on February 20, observed the Nova with a compound Aquilæ, and S Cephei.

spectroscope of a dispersion sufficient just to show the nickel AstroNOMICAL Possibilities AT CONSIDERABLE Alti: appeared bright. Their identification was easy by means of a

line between the D lines. The hydrogen lines C, F, and Hy TUDES.-Prof. Pickering, in No. 3079 of the Astronomische hyclrogen tube in front of the slit. These three lines did not Nachrichten, relates some interesting facts in an article on

exactly coincide with the lines of the comparison spectrum, but “Astronomical Possibilities at Considerable Altitudes.” They

were displaced considerably towards the red, without, however, are gleaned from observations made at the Boyden Station of

separating completely from the artificial lines, since they were the Harvard College Observatory, which is situated two miles

very broad. The continuous spectium appeared faint, owing to from the city of Arequipa, Peru, in latitude 16° 24' S., and

the comparatively high dispersion ; and with certainty only

the longitude 4h. 45m. 3os. W. of Greenwich, and at an altitude

dark broad F line was recognizable, situate towards the more of 8060 feet above sea-level. The air there is so clear and refrangible side, distinctly separated from the bright line in the steady that 6'5 magnitude stars are picked out by the naked eye spectrum. with great ease, and, when the moon is not too bright, the

Between C and F, a large number of bright lines could be eleven Pleiads can always be counted. The nebula in Andro.

seen, but most of them were too saint to be fixed with cer. meda forms also a very conspicuous object," appearing larger

tainty. In the case of two brighter lines near F, myself and than the moon," while, in ihe 13-inch Clark refractor, “The

Mr. Frost, who assisted in the observations, succeeded in whole photographic region of the great Orion nebula, first

making very certain wavelength determinations; we found shown in the Harvard photographs of 1887, is clearly visible

492'5 uu for the fainter of the two lines, which appeared broad to the eye,” rendering it the "most splendid object in

and fuzzy on both edges. and 501 6 uue for the brighter line. The the stellar universe.” The steadiness of the atmosphere limit of error is to be taken at about = '3 uu, and it results from is also very much remarked there, so much so that a scale

the observation with certainty that the brighter line is not idenof steadiness has been adopted. Some of the brightest stars have tical with the double line of the air spectrum or with the been noticed to have as many as six complete

diffraction rings

brightest line of the nebula, and still less the other with the round them ; while around these, when the seeing was denomi

second nebula line. From Young's list of lines most frequent nated as “perfect," twelve rings have been counted. “Boiling”

in the chromosphere, it follows that near F only the iwo groups was also found to be sometimes completely eliminated, for, in

of lines, 50187, 501 59, and 493 44, 492 43, 492'24, 49192 observing bodies of the solar system with a 13-inch and a power frequently appear bright. There is no doubt that both lines in of 400, “it was frequently impossible to detect any wavering of

the spectrum of the Nova are chromosphere lines, and this result the edges of the disk.”

appears to me of great importance, in so far as it is made The conclusion that Prof. Pickering comes to with regard to probable that the line observed in Nova Cygni (1876)—W.L. the position of future Observatories is that “moderate altitude is

500 ure # 1uu- which, during the gradual lading of the star, a most desirable qualification,” while “for transparent skies

alone remained, was a chromosphere line, and not the nebula one must approach the tropics, and for steady seeing one must line. have an extremely dry climate."

“Further, both myself and Mr. Frost saw probably the mag. INCREASE OF THE EARTH'S SHADOW DURING LUNAR

nesium lines, certainly the sodium lines brighi, as also two lines ECLIPSES. - In a memoir with the title "Die Vergrösserung

between b and D, one of which probably was the well-known des Erdschattens bei Mondfinsternissen” (Abhandlungen der

chromosphere line W.L. 531 72, also observed in Nova Cygni. math. phys. Classe der k. Sachsischen Ges. d. Wissenschaften,

By direct comparison with the hydrocarbon spectrum, the vol. xvii., Lepzig, 1891), Dr. Hartmann published the results of brightest band of which nearly coincides with the b group, and an investigation into the amount by which the earth's atmosphere with the sodium flame, b and D were identified. Mr. Frost increases the diameter of the section of the shadow during a lunar could see a displacement of the D lines in the star spectrum eclipse. An abstract of the memoir appears in the annual

with respect to the comparison spectrum. There was no inreport of the Royal Astronomical Society, which has just been dication of hydrocarbon bands in the spectrum of the Nova. issued. Since the time of Tobias Mayer (1750) the coefficient

“Up to the present eleven mostly very good spectrographic and has been assumed to represent this increase, although nothing photographs have been taken ; they were obtained by means of a is known as to the manner in which this quantity was determined.

small spectrograph connected to ine photographic refractor of Dr. Hartmann has reduced all the observations of lunar eclipses 34 cm. aperture. The dispersion is only small, but in the observed independently by several astronomers during this cen

small spectrum of 10 mm. length, extending from F 10 H, tury, and has deduced the increase of the diameter of the shadow

much detail is discernible. The illuminating power of the from them. The result of a comprehensive discussion of 2920 apparatus is so great, in spite of the narrow slit employed, that observations of the contact of the shadow with well-defined lunar even now an exposure of 40 minutes is sufficient to obtain an formations is, that the increase of the semi-diameter of the image suitable for measurement. The bright hydrogen lines shadow is 48" 62 for mean lunar parallax. This corresponds to a

F, Hy, h, H, and the calcium line Hy, are very broad; and,

as already announced, the corresponding dark lines of a second coefficient of increase =

The result may perhaps be spectrum are displaced with respect to the bright lines towards

50-79 changed 2" or 3" by a discussion of new observations, but not

the violet, and in spite of the breadth of the latier, are almost more, so it seems desirable that the value of sy should be used, in the ultra-violet visible, but they are too faint for any approxi

entirely separated. There are still some of the hydrogen lines when required, instead of Mayer's value of do.

mately certain observation.

"In the last few days the spectrum has changed, inasmuch as THE NEW STAR IN AURIGA.

in the broad bright lines Hy, h, H, and H, (F is only traced on

plates u hich are over-exposed for the middle of the photographic The new star is rapidly getting more and more difficult of spectrum)

, two maxima of intensity are plainly discernible, and, observation in cons:quence of its waning light. There is as in each of the corresponding dark lines, a narrow bright line very little change in its spectrum, and what change there is is has appeared. From the measurements, a connection between not in the direction recorded of Nova Cygni, so it seems pretty these and the hydrogen lines appears beyond doubt, and it is

I

« AnteriorContinuar »