398 



NATURE 



[Feb. 25, I J 



he considers, be improved by using more acciuate values of 

 the constants, and of the epoch for which t = o. The magni- 

 tude corresponding to this latter epoch is 7 '73- Considering 

 that there is evidence to show that the Andromeda nebula is 

 in part at least, a star-cluster consisting of a vast number of 

 faint stars, Prof. Seeliger thinks it not improbable that the 

 blazing forth of the A'oz'a may have been due to a collision 

 which caused an enormous development of heat and light. At 

 all events, the fact that his formula represents the observations 

 tolerably well appears to him to be sufficient evidence to show 

 that the supposed conditions are not, in the main, at variance 

 with the actual circumstances of the case. 



Present State of the Solar Activity. — The sunspot 

 ma.\imum, after some remarkable oscillations, was definitely 

 attained about the close of 18S3, the intereal from the period of 

 minimum having been nearly two years longer than usual. Since 

 that date there has been a steady diminution in both the numbers 

 and areas of the sunspots. M. R. Wolf gives (Compies rendns, 

 vol. c. No. 3, and vol. cii. No. 3) the following values for his 

 relative numbers for the last three years : 1883, 63' 7 ; 1884, 63 '3 ; 

 1885, 50'3. The diminution in the last part of 1SS5 was parti- 

 cularly marked, there having been a vigorous rally in the months 

 of May, June, and July, followed by a rapid decline. The 

 relative numbers for the last three months of the year fell far 

 below the mean of the twelvemonth. The figures given by 

 M. Tacchini closely correspond to those given by M. Wolf, as 

 the following table will show. The last three columns give 

 Tacchini's numbers : — 



lanuai7 

 February 

 March ... 

 April . . 

 May 

 June 



July ... 

 August . . . 

 September 

 October 

 November 

 December 



31 '4 

 67-2 

 466 



546 

 So'5 



S2-I 



61 '4 



477 

 43 '4 

 42-6 

 26-8 

 18-9 



frequency 



i9'57 • 



25-Si . 



:6-23 . 



iS'io . 



18-68 . 



22-36 . 



15-41 . 



1 1 -20 



9-14 . 



12-55 ■ 



6-35 ■ 



4-84 . 



Relative 



43'19 

 77-33 

 44-92 

 56-86 

 86-21 

 13276 

 90-22 

 44-70 

 59-20 

 55-64 

 22-90 

 21-44 



Daily 



groups 



4"33 

 5.96 

 2-92 

 3 -48 

 5-80 

 5 -21 

 4-45 

 3 "40 

 3-31 

 3-09 

 2-30 



2"I2 



Faculre have not shown so rapid a decline, but there has 

 been a distinct falling off in these also ; the diflTerence, however, 

 is at present noticed rather in a loss of brilliancy than of 

 apparent area. But hitherto the prominences have shown but 

 slight indications of a participation in the falling oft" so strongly 

 exhibited by the spots. The following numbers, derived froin 

 papers by the Rev. S. J. Perry in the Observatory for February 

 1S85 and 1886, show indeed a slight increase of energy for 1SS5 

 over 1884 : — 



Mean height of Mean extent 



chromosphere. Mean height of of 



Year excluding prominences prominence 



prominences arc 



7-93 

 8-04 

 8-24 

 S-27 

 7-94 

 S-00 



23-46 

 24-61 



24-55 

 27-23 

 25-74 

 28 -67 



23 21 



33 iS 



40 57 



41 24 

 29 6 

 28 25 



Mean 

 1880-1SS 



S-07 



25-71 



32 45 



The mean extent of prominence arc is thus the only element 

 which seems to point to the ma.ximum being past. 



But if the prominences do not show any close correspondence 

 to the behaviour of the spots, M. Wolf finds that the variations 

 of magnetic declination have responded to their changes fairly 

 closely. In the paper alluded to above he gives, side by side 

 with his "relative" spot numbers, the monthly means of the 

 variations in magnetic declination as observed at Milan. The 

 mean obser\'ed value for 1885 is 7' -95, whilst 7'-88 is the mean 

 value computed from the formula M. Wolf had deduced in 

 former years for Milan, v = 5'-62 -(• 0-045 ''> where r is the 

 relative sunspot number for the year. 



Prof. Sporer points out ( CoiiipUs rendiis, vol. ci. No. 26) that 

 the spots have not been equally distributed between the two 



hemispheres during the period of maximum, but that throughout 

 the years 1883, 1884, and 1885 there has been a nearly constant 

 predominance of southern spots over northern ; whereas in the 

 period from minimum to the end of 18S2 the predominance 

 rested, on the whole, with the northern hemisphere. This 

 alteration has also been accompanied by somewhat of a check in 

 the regularity of the progress of the spots towards the equator, 

 which is usually so marked in the interval from one minimum to 

 the next. 



ASTRONOMICAL PHENOMENA FOR THE 

 WEEK 1886 FEBRUARY 2Z— MARCH 6 



/"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 February 28 

 Sun rises, 6I1. 49m. ; souths, I2h. 12m. 41 -5s. ; sets, I7h. 36m. ; 



decl. on meridian, 7° 52' S. : Sidereal Time at Sunset, 



4h. lom. 

 Moon (New on March 5) rises, 3h. 39m. ; souths, 8h. 6m. ; 



sets, I2h. 34m. ; decl. on meridian, 18° 16' S. 



Europe. 

 Mars in opposition to the Sun. 

 Mercury in conjunction with and 0° 8' north 



of the Moon. 



Variab'.c-Stars 



U Cephei ... 

 Algol 



A Tauri 

 R Lyncis 

 ^ Geminorum 



V Geminorum 

 5 Libras 



U Coronce ... 



V Coronffi ... 

 U Ophiuchi... 



X Sagittarii... 



W Sagittarii 

 /3 Lyrse 

 5 Cephei 

 R Aquarii ... 

 M signifies 



o 52-2 

 3 0-8, 



3 54-4 



6 51-9 



6 57-4 ■ 



7 16-8 . 



14 54-9 • 



15 '3-6 . 

 15 45-5 . 

 17 10-8 . 



Si i6N. 

 40 31 N. 



12 10 N. 



55 29 N. 

 20 44 N. 



13 T9N. 

 8 4S. 



32 4N. 



39 55 N. 



I 20 N. 



Mar. 3, 20 57 m 

 Feb. 28, 23 24 m 

 Mar. 3, 20 13 m 

 „ 2, iS 12 m 

 ,,2, M 



,, 4, 21 30 M 

 ,, 6, Af 



,, 4, 22 36 m 

 ,, 5, 20 13 m 

 „ 5, '" 



„ 3, 5 28 M 



and at intervals of 20 8 



17 40-4 ... 27 47 S. 



17 57-8. 



18 45-9 . 



22 24-9 



23 37-9 • 



29 35 S. 

 33 14 N. 

 57 50 N. 

 IS 55 S. 



Mar. 



ndary i 



5, 21 30 M 



6, 21 30 M 

 6, o o m„ 



3, o o A/ 

 3, M 



Meteor Showers 



The first week in March furnishes the most favourable nights 

 of the month for meteor observation, but none of the great 

 periodical showers occur at this time. Amongst the radiants 

 represented are the following : — 



Near 7 Orionis, R. A. 80°, Decl. 6° N. ; near a Persei, R.A. 

 50°, Decl. 48° N. ; near 77 Boatis, R.A. 205°, Decl. 17° N. ; 

 near { Sagittarii, R.A. 280°, Decl. 17° S. ; Ursa Major. R.A. 

 180°, Decl. 60° N. 



BIOLOGICAL NOTES 

 Continuity of Protoplasm. — M. L. Olivier proposes, in 

 the Comples reridus, the following methods for determining the 

 connection between the protoplasmic contents of adjacent cells : 

 — (i) Photography. This distinctly reveals the perforation by 

 canals of the cell-walls, when photographed direct with a magni- 

 fying [Jower of 300-700 diams. (2) Direct observation, with 



