45^ 



NA TURE 



[September 6, 1894 



apparent dnuble was a canal from Fons Juvenle and a north 

 b.anch of Tiihonu.. The latter observations have an interest, 

 since the canal Ganges has been reported as having been seen 

 doable at the Lick Observatory. ,,,-.. 



A circular just distributed by the Centralstelle fur Astrono - 

 mischeTelegfamme. Kiel, states that a telegram, of which ih e 

 following IS a translation, was received fronn feramo on Au^a» t 

 -I— "Greenish-white spot on the northern cap of Mar» . 

 Length thirty to forty degrees. Nix borea apparently cover s 

 Mate aiiiUliu'". CeruUi." 



THE Mass of Jupiter.— It was more than twenty years ago. 

 Prof Simon Newcomb reminds us in the Aslronomische 

 Nac'hrichlen No. 3249. ihat he called attention to the great 

 value of observations on the minor planet Polyhymnia for de- 

 termining the mass of Jupiter. Prof. G C^ Comstock s com- 

 puiations of the special perturbations ol the elements of the 

 former planet from the date of discovery in Ib54. together with 

 the observations made during the oppoiUion of iSSS. have 

 enabled Prof. Newcomb to make this determination. 1 he re- 

 sult obtained shows that the mass of Jupiter is ,-3-^^ P»'' '''« 

 mass of the .sun. Other determinations of Jupiter's mass^are 

 shown in the following table, and also the weights assigned to 

 them by Prof. Newcomb, who proposes to regard the weighted 

 mean as definitive, and to use that mass in his work on the 

 planetary theories. ^^^.^^^.^ Weight of 



Mass. Dcterminauon. 

 All observations on the satellites ... 104782 ... I 

 Action on Faye's Comet (Mr.Uer) ... 104779 ... I 

 Action on Themis (Krueger) ... I04754 ■•■ 5 



Action on Saturn (Hill) 1047-3^ ••• 7 



Action on Polyhymnia 1047'34 ••• 20 



Action on Winnecke's Comet (v. 



Haerdtl) '047 '7 ■■• "O 



Weighted mean 104735 ± °o65 



It is pointed out that in the interests of the astronomy of the 

 future it is very desirable to apply Gill's heiiometer method 

 to the continuous observation of a selected number ol minor 

 planets. 



AMERICAN ASSOCIATION FOR THE 



ADVANCEMENT OF SCIENCE. 



THE forty third annual meeting of the American Association 

 for the Advancement of Science was held at Brooklyn, 

 N.Y., from August, 16-22. • , 1 „ u.ij 



The marvel is that no meeting had previously been held 

 in that great city. Overshadowed as it is by the greater 

 metropolis of New York, its next neighbour, many strangers 

 fail to realise that Brooklyn is one of the great cities of the 

 world. By a recent act of the legislature its area has been 

 doubled, and its population now exceeds one million, making 

 it the fourth city in America; until the last census it was the 

 third, but Chicago has now outstripped it. 



Not merely as a portion of the metropolis of America, but 

 also in those features which arc distinctively peculiar to itself, 

 Brooklyn offers unrivalled attractions to men of science. 1 he 

 maiisive bridge which spans the East Kiver connecting it with 

 New York is a world-renowned triumph of engineering. ine 

 United States Navy Yard attracts the attention of those who study 

 applied science, and eleven thousand manufacluring establish- 

 ments provide valuable object-lessons. .... , ,, 



The city is niso notable for educational institutions of the 

 bat character, including the Pratt Institution, the Packer the 

 Polytechnic, the Long Island Medical College, the 'loogland 

 BioW'cal Laboratory, a large and well-equipped High School 

 for each «x, and several Roman Catholic Seminaries. 



A marked feature of recent meetings of the Association has 

 been the increasing number of affiliated societies which hold 

 meetings in connection with the general Association. 1 wo new 

 accessions bring the numher of these already up to nine, an. 

 next year the American Botanical Society will still further .swell 

 the list which now indu Ics the American M.ithematical Society, 

 the Society for Promoting Kngineciing K<lucaiion, the Society 

 for the Promotion of Agricultural Science, the American Micro- 

 «»pical Society, the (ieoL.gical Society of America, 'he Associa- 

 tion of Economic Entomologists, ihc American Chemical 



Society, (he Association of Slate Weather Services, anl the 

 American Forestry Association. 



The citizens of Brooklyn entered into the arrangements with 

 an evident determination to do everything to insure the success 

 of the meeting. The reception at the Academy of Music and 

 the Art Building, on the opening evening, was perfect in all its 

 details. The excursions were of unusual number and variety, 

 and included features of exceptional scienlilic interest, such as 

 dredging expeditions by the steamer Fish Ha-.ck, furnished by 

 the Unite<i States Government. Special mention is also due to 

 the elegant excursion to West End. and entertainment furnished 

 by Mrs. Herrman, a patron of the Association, and of the 

 sterling silver badges of her own design given as souvenirs. 



The weather continued cool and comfovl.ible throughout, so 

 that all the external conditions were as favourable as possible. 

 Teleologists even found evidence of providence and previsiori 

 in the unusual circumstance that nine century plants bloomed 

 together to welcome the coming Association. 



The attendance of members was well above the average of 

 recent years, and if to the registry of thegeneral Association be 

 added the names of specialists attending the aftiliated societies, 

 it will raise the total to an aggregate comparing favourably 

 with the largest meetings, notwithstanding that the depression 

 of business and the fear of detention by railroad strikes exerted 

 a deterrent influence. ■ c 1 . 



Three evenings were occupied with popular scientihc lectures 

 Paul du Chaillu spoke on the Vikings, their civilisation and 

 expeditions; Edward D. Cope, on the relation of human 

 structure and physiognomy to those of the other mammalia ; 

 and B. E. Fernow, on the battle of the forest. virilism 



The annual address of the retiring president. Prof. William 

 Harkness, was on the magnitude of the solar system. An 

 exhaustive account was given of the various methods of 

 measuring the sun'.s distance. Many of Prof. Harkness hearer, 

 were surprised to learn that but little accuracy has been 

 attained for many years. He states as his conclusion after 

 comparing all the corrected results of these various methods, 

 that the sun's distance is 92,797,000 miles with a probable 

 error of 59,700, and the diameter of the solar system, measured 

 by that of its outermost member, the planet Neptune, 

 5,578,400,000 miles. ^ , ,. 



The address of Vice-President George C. Comstock, on binary 

 stars, was of interest, as will be seen from the fo lowing extracts 

 After a general review of the subject, he said that the orbits 

 of forty-two binary stars based on motion of over 80 .have been 

 computed. The shortest are S Equulei and -c Pegasi, each less 



'""fVa^ncrr presents a curious study. Two stars les^ than a 

 second apart revolve in an ellipse ; a third star 6 aistan 

 revolves in loops, suggesting an invisible ':""'Pan>0"- 2"' 

 binaries have been discovered by the spectroscope : 3 A«"-'6«. 

 revolving in a period of four days; a Virgmis, four days, 

 c- Ursa: Majoris, 105 days ; and Algol, three days. 



The masses of the visual and of spectroscopic hinar es are 

 derived by totally different inetliods, but both cUasses of bodies 

 indicate that the sun is an undersized star, a resuir that is con- 

 firmed by other and independent lines ol '»^«"e';"°"- ^^^^i' 

 small r.ange of values presented by the m.^sses of the stars is 

 rema.kable, and points to an unexplaine.l uniformity of size m 

 the heavenly bodies, the avei.ige component of a double star 

 having a mass somewhat greater than the m.ass of he earth. 



If binary stars are classified with respect to their type of 

 spect.um. It will be found that on the ave.ago the •''^'""'^'^ »' " 

 s ar possessing a Sirian spectrum is about three ""'^^ ^\ K'^J 

 as that of a star possessing a solar spectrum, and it will further 

 be found that although stars of the hirian 'Vl'-^ "7' °" '^* 

 whole, more numerous than solar stars, binaries of solar type 

 outnumber their Sirian fellows three to one 



Four-fifths of the binaries, with periods of less than two 

 hundred years, h.ave orbits sm.iller than Neptune, while the 

 fastest have orbits between Jupiter and S.ilurn. ,,,,„,ntl 



A combination of measured amounts of light "''h »le™«W 

 of orbit is mass-brighlness,or " candle-power l";';^"'" /^oung). 

 •y Leonishas more than loootimesthemass-brigUnessofGiCygm 

 Iprobably. Confining ourselves 'o'hose with well- lelermiicd 

 orbits, we find at extremes of the 1st .^ Urs.e M ,| '":. « h "i 

 mass-brightness fifty times that of 70 Ol-hiuc In. ' ^^ ■^^"^f 

 brightness of the sun is jirobably not much greater than that ol 



'°U 'lt"fong been known that if the components of a double 



NO. 1297, VOL. 50] 



