86 



NA rURE 



\_Nov. 25, 1886 



ASTRONOMICAL PHENOMENA FOR THE 



WEEK 18S6 NOVEMBER 2.%— DECEMBER 4 

 /pOR the reckoning of time the civil day, commencing at 

 Greenwich mean midnight, counting the hours on to 24, 

 is here employed.) 



At Greenwich on November 28 

 Sun rises, 7h. 42m. ; souths, iih. 48m. lo'4s. ; sets, I5h. 55m. ; 

 decl. on meridian, 21° 21' S. : Sidereal Time at Sunset, 

 2oh. 25m. 

 Moon (three days after New) rises, gh. 52m. ; souths, I4h. 15m. ; 

 sets, l8h. 39m. ; decl. on meridian, 19° 7' S. 

 Planet Rises Souths Sets Ded. on meridian 



Mercury ... S 40 



Venus 7 II 



Mars 10 27 



Jupiter 3 55 



Saturn 19 5* 



12 35 ... 16 30 ... 23 II S. 



II 43 ... 15 53 ... 20 51 S. 



14 14 ... 18 I ... 24 15 s. 



9 12 ... 14 29 ... 9 14 S. 



7 ... u 9 ... 21 25 N. 



* Indicates that the rising is that of the preceding evening. 

 Occultation of Slar by the Moon (visible at Greenwich) 



Corresponding 

 Dec. Star Mag. Disap. Reap. angles from ver- 



*^ te.v to right for 



h. m. h. m. '"'■"'='^ ""j'S' 



3 ... /;! Aquavii ... 5! ... 17 8 ... 18 30 ... 116 286 

 Dec. h. 



3 ••• 5 •■■ Venus in superior conjunction with the Sun. 



3 ... 12 ... Mercury in inferior conjunction with the Sun. 



4 ••■ 4 ■■• Mercury at least distance from the Sun. 



Variable Stars 

 Star R.A. Decl. 



h. m. „ , h. m. 



U Cephei o 52-2 ... 81 16 N. ... Nov. 28, 2 27 m 



Dec. 3, 2 6 VI 



Algol 3 0-8 ... 40 31 N. ... ,, I, 5 38 m 



,, 4, 2 27 m 



^Geminorum ... 6 57-4 ... 20 44 N. ... Nov. 29, o o tii 



Dec. 4, o o M 



U Monocerotis ... 725-4... 9 32 S. ... Nov. 28, m 



S Cancri 8 37-4 .. 19 27 N. ... ,, 28, 3 9 m 



T Urss Majoris ... 12 31-2 ... 60 7 N, ... ,, 29, M 



5 Virginis 13 27-1 ... 6 37 S. ... ,, 30, M 



^ Lyra; 18 45'9 ■■ 33 14 N. ... ,, 28, 21 30 m 



Dec. 2, 5 o m 



R Lyrae iS 51-9 ... 43 48 N. ... Nov. 28, M 



T) Aquila; 19 467 ... o 43 N. ... Dec. i, 2 30 M 



6 Cephei 22 24-9 ... 57 50 N. ... Nov. 30, 2 o m 



^/signifies maximum ; tn minimum. 

 Meteor Showers 

 The chief shower of the week is that of the Taurids ; R A. 

 60°, Decl. 49' N. Other radiants active at this time are as 

 follows: — Near 7) Persei, R.A. 44°, Decl. 56° N., slow, faint 

 meteors; near a Canum Venaticorum, R.A. 194°, Decl. 43° N., 

 very swift, streak-leaving meteors; from Leo Minor, R.A 

 155°, Decl. 36° N. ; from near tj Ursre Majoris, R.A. 208°, 

 Decl. 43' N. Fireball dates, November 29 and December 2. 



TEN YEARS' PROGRESS IN ASTRONOMV^ 

 II. 

 'J^HE S liar Spectrum. — In 1877 Dr. Henry Draper, of New 

 York, by aseriesof most laborious, time-consuming, and ex- 

 pensive researches, discovered the presence of oxygen in the sun, 

 evidenced in his photographs, not by tine d.irk lines, as in the 

 case of elements preiiously recognised, but by bright, hazy 

 bands. It is difficult to assign any reason why this gas should 

 behave so peculiarly and so differently from others, and for this 

 reason many high authorities are indisposed to accept the dis- 

 covery. But the evidence of the photographs seems fairly to 

 outweigh any such purely negitive theoretical objections. 



Other advances have been made in the study of the spectrum, 

 due mainly to the great improvements in spectroscopic appa- 

 ratus. Until recently it has not been easy to decide with 

 certainty as to some lines in the spectrum whether they were of 



' "Ten Years' Progress in Astronomy. 1876-86," by Prof. C. A. Young. 

 Read May 17, 1886, before the New York Academy of Sciences. Continued 

 from p. 6y. 



solar or telluric origin ; the great bands known as A and B, for 

 instance. It was only in 1883 that the Russian, Egoroff, suc- 

 ceeded in proving that these are produced by the o.fygen in the 

 earth's atmosphere. In his experiments, on a scale previously 

 unknown, the light was transmitted through tubes more than 

 60 feet in length, closed at the end with transparent plates, 

 and filled with condensed gas. 



It was quite early pointed out that the sun's rotation ought to 

 produce a shift in the position of lines in the spectrum according 

 as the light is derived from the advancing or receding edge of 

 the solar disk, and ZoUner thought he could perceive it. The 

 earliest measures, however, were, I believe, those obtained 

 independently by Vogel and the writer in 1876. In the great 

 bisulphide of carbon spectroscope of Thollon the displacement 

 becomes easy of observation ; and very recently Cornu, by taking 

 .advantage of it, and by an extremely ingenious arrangement for 

 making a small image of the sun to oscillate across the spectro- 

 scope slit two or three times a second, has been able to discrimi- 

 nate at a glance between the telluric and solar lines ; the former 

 stand firm and fast, while the latter seem to wave back and 

 forlh. 



In this connection also should be mentioned the great map 

 of the solar spectrum, for which Thollon received the Lalande 

 Prize of the French Academy of Sciences last January, and the 

 still more accurate and important map photographed by Prof. 

 Rowland, by means of his wonderful diffraction-gratings, and 

 now in course of publication. Nor would it be just either to 

 omit the earlier and less accurate maps of Fievez and Vogel, 

 which, when published, were as far in advance of anything 

 before them as they are behind the new ones ; nor the maps just 

 made by Prof. Smyth, of Edinburgh. 



It w.as in connection with the construction of such a map by 

 Mr. Lockyer, that he was led to his theory of the compound 

 nature of the so-called chemical elements, partly as a result of 

 his comparisons of the spectra of different substances with the 

 solar spectrum, and partly in consequence of considerations 

 drawn from certain phenomena observed in the solar and stellar 

 spectra themselves. His first paper on the subject was read late 

 in 1S78. This "working hypothesis," as its author calls it, has 

 met with much discussion, favourable and unfavourable. It 

 unquestionably removes many difficulties and explains many 

 puzzling phenomena ; at the same time there are very serious 

 objections to it, and some of the arguments upon which Mr. 

 Lockyer originally laid much stress have turned out unsound. 

 For instance, he made a great point of the fact that, after all 

 precautions are taken to remove impurities, several elementary 

 substances show in their spectra common lines^" basic lines" 

 he called them — indicating, as he thought, a common com- 

 ponent. He found in the solar spectrum about seventy of these 

 " basic lines. " Now, under the high dispersion of our newer 

 spectroscopes, these lines, which were single to his instruments, 

 almost without exception dissolve into pairs and triplets, and 

 withdraw their support from his theory. 



I suppose that at present the weight of scientific opinion is 

 against him ; but, for one, I do not believe his battle is lost. In 

 vieu- of the law of Dulong and Petit, which establishes a rela- 

 tion between the atomic weight and specific heat of bodies, it 

 seems to be pretty certain that hydrjgen cannot be the element- 

 ary " nrsloff" out of which all other elements are made by 

 building up, as he at first seemed disposed to maintain ; this 

 element stands apparently on no different footing from the rest. 

 But I see no reason why the elements, as we know them, may 

 not constitute one class of bodies by themselves, all built up out 

 of some as yet more elemental substanc; or substances. The 

 *' periodic law" of Mendelejeff suggests such a relation. And 

 our received theories so stumble, hesitate, and falter in their 

 account of many of the simplest phenomena of the solar and 

 stellar atmospheres, that a strong presumption still remains in 

 favour of the new hypothesis. I am not prepared to accept it 

 yet ; but certainly not to reject it. 



The Chronnsphere. — The study of the chromosphere and 

 prominences has been kept up, very systematically and statistic- 

 ally, by Tacchini in Italy, and with less continuity, but still assi- 

 duously, by several other observers. I do not know, however, 

 that any new results of much importance have been arrived at. 

 The list of bright lines visible in their spectra has been a good 

 deal enlarged ; and Trouvelot thinks he has observed dark pro- 

 minences — objective forms that show, black but active, upon 

 the background of bright scarlet hydrogen in the surrounding 

 chromospheric clouds. It may be that he is right ; but, so far 



