Aug. 



24, 1876] 



NATURE 



357 



OUR ASTRONOMICAL COLUMN 

 The Total Solar Eclipse of 1882, May 17.— The 

 following elements of this eclipse depend upon the lunar 

 tables of Damoiseau and the solar tables of Carlini, and 

 are therefore not intended to be used in a calculation of 

 the precise circumstances for any place. They will, never- 

 theless, ^serve to afford a better idea of the character of 

 the eclipse near the central track than can be obtained 

 from Hallaschka's map in h\s Elementa Eclipsium, where 

 by an error of calculation the eclipse is shown broadly 

 annular. 



Conjunction in R.A., 1882, May 16, at igh. 42m. 25s. G.M.T. 



R-A 5°3 5^ 53-3 



Moon's hourly motion in R, A. ... 36 14 "4 



Sun's „ , 2 28-6 



Moon s declination 19 38 41 'gN. 



Sun's „ 19 19 42 'oN. 



Moon's hourly motion in dec!. ... 36 I4'4 N. 



Sun's ,, „ ,, 2 286 N. 



Moon's horizontal parallax ... ... 58 1 5 ' i 



Sun's ,, ,, ... ... 8'8 



Moon's true semi-diameter ... ... 15 52*4 



Sun's ,, ,, 15 48*8 



The equation of time is 3m. 50s., subtract! ve from 

 apparent, and the sidereal time at mean noon. May 17, 

 3h. 40m. 192s. 



Instead, therefore, of being broadly annular, the eclipse 

 will be narrowly total on the central belt. 



h. m. , , , , 



Central eclipse begins 17 55'0 in Long. 3 26 W., Lat. 10 32 N. 

 » M at noon „ 63 27 E., ,, 38 27 N. 



„ „ ends 21 208 „ 138 29 E., „ 2517N. 



The eclipse is total in Upper Egypt and the Peninsula 

 of Sinai, points on the central hne being 32° 25' E., 26° 

 57' N., and 34° 23' E., 27° 57' N. 



These elements also give totality for about twenty 

 seconds at Shanghai : middle at jh. 21 •2m., local mean 

 time, sun's altitude, 1 7°. 



Comets of 1847. — In the last number of the ^j/r<7- 

 nomische Nachrichten, Dr. Schur, of the Observatory at 

 Strasburg, has given definitive parabolic elements for the 

 comet discovered by Schweizer at Moscow, on Aug. 31, 

 and last seen at Pulkowa on Nov. 28 — an isolated obser- 

 vation. Elliptical elements had been assigned to this 

 body, but the more complete computation by Dr. Schur 

 shows that there is no sensible deviation from the 

 parabola. 



Greater interest attaches to another comet of the same 

 year — that detected on July 20, by Brorsen at Altona, 

 which was observed by Riimker till Sept. 12. The 

 observations can hardly yet be considered as having been 

 thoroughly discussed, though it may be presumed that 

 D'Arrest used the last Hamburg observation in calcu- 

 lating his second elHpse {Ast. Nach., No. 662), and Dr. 

 Gould investigated elements with the whole, or nearly 

 the whole, of the observations before him. 



D'Arrest, by his second calculation, found the period 

 seventy-five years ; Dr. Gould gave eighty-one years ; 

 hence this comet has been considered to form one of the 

 singular group which appear to revolve in something less 

 than the period of Uranus ; it must, however, at present 

 be regarded as the least certain of the number, with 

 respect to length of revolution. It presents a case where, 

 as Dr. Gould remarks, very small changes in the funda- 

 mental places, even the slight change of the parallax due 

 to more accurate determination of the comet's distance 

 is " sufficient to change materially the form of the result- 

 ant orbit and the period deduced." His final elements 

 exhibit a decided preponderance of sign in the errors when 

 compared with the August observations, though he ap- 

 pears to have suspected the cause to have been mainly 

 the difficulty attending exact computation from the ele- 



ments in such a case. The observations will be found in 

 a collective form in his paper concluded in vol. i., No. 19, 

 of the Astronomical Journal — a periodical, by the way, 

 of which it is difficult now to procure complete sets. The 

 greater number are also found in Astrotiomische Nach- 

 richten, vol. xxvi. D'Arrest furnishes no particulars 

 of his second calculation, but gives the elements the 

 preference over his first set, in which the period of revo- 

 lution was considerably longer. 



A further calculation may possibly lead to a more de- 

 finitive value for the major axis ; at present it appears 

 that when the comet is re-discovered it is likely to be by 

 accident rather than from any approximate knowledge of 

 the epoch of ensuing perihelion passage and organised 

 search, 



A still more worthy matter of investigation, however, is 

 the orbit of Olbers' Comet of 18 15, due, according to 

 Bessel, in less than eleven years. It is pretty certain that, 

 with the introduction of improved solar tables and star- 

 places for new reduction of such original observations as 

 we possess, the fundamental positions might furnish a 

 still more reliable orbit for 181 5, while the re- calculation 

 of the perturbations from more exact values of the masses 

 than were at Bessel's command, may lead to a nearer 

 determination of the time of next perihelion passage, 

 which he has fixed to 1887, February 9. 



FRENCH ASSOCIATION FOR THE ADVANCE- 

 MENT OF SCIENCE 



HTHIS year's Congress was opened at the Hotel de 

 -*■ Ville, Clermont, on Friday, August 18, under the 

 presidency of Prof. Dumas, the well-known chemist and 

 the perpetual secretary of the Academy of Sciences. M. 

 Dumas praised in warm terms the spirit of individual initia- 

 tive so largely developed in England, and he compared the 

 British Association with her younger sister, the French 

 Association. He spoke in high terms of English men of 

 science, and referred to the Exhibition of 1 851, and the 

 important results which have followed it in the develop- 

 ment of permanent scientific institutions in England. 

 M. Dumas acknowledged the zeal of the French Govern- 

 ment in helping science, and he showed that science must 

 be promoted not only by benevolent and intelligent indi- 

 viduals, but also by the State. He, in eloquent terms, 

 presented to the assembly the testimony of his long-con- 

 tinued labours extending over a period of more than sixty 

 years, as a proof that science was conducive only to 

 happiness. He advised men of science not to meddle 

 either with theology or with philosophy, but to leave all 

 questions in these regions in the hands of theologians and 

 philosophers. The province open to science is large 

 enough to give every satisfaction to the widest ambition. 



The address was received with enthusiasm. The mayor 

 of Clermont, M. Moinier, a barrister by profession, de- 

 livered a very sensible address, making allusion to the so- 

 called " grands jours d'Auvergne," when many centuries 

 ago legislators held their meetings in the very place where 

 a parliament of science was then assembled. He said, 

 moreover, that science, which was ignored in those days, 

 was supposed now to have the duty of ruling the rulers of 

 mankind. 



M. Cornu then addressed the assembly on the present 

 condition of the Association, which is eminently satis- 

 factory. One of the most important announcements he 

 had to make was that the Association, since its last meet- 

 ing, has been recognised by Government as " of public 

 utility," which is equivalent to the granting of a charter 

 in England, and which will not only be of advantage to 

 the Association, but, we believe, wiU enable the Associa- 

 tion to be of greater benefit both to France and to science. 

 To celebrate this episode in its history, M. d'Eichthal, to 

 whose efforts it was largely owing that the privilege was 



