THE APPEARANCE OF THE CORONA. 91 



comparatively narrow bright ring of light round the sun, flanked 

 1>\ two enormous extensions east and west in the plane of the 

 sun's equator. It was impossible to overlook so striking a 

 change ; and on comparing the drawings of 1878 with one which 

 had been made eleven years previously in the eclipse of 1867 by 

 (irosi-h. it was >een that the two coronas were almost of exactly 

 the same shape. This striking change was at once connected 

 with the change which had taken place in the same time in the 

 sun's surface. 1870 and 1871 were years in which the spots 

 ii}K)n the sun were unusually numerous and large; 1868 and 

 1878, on the other hand, were years when the sun was almost 

 entirely free from spots. Looking back to the eclipse of 1860, 

 which was very fully observed, chiefly in Spain, and of which 

 Mr. Weedon's drawing in the plate on p. 86 may be taken as 

 a specimen, the corona was seen to be utterly unlike those of 

 1867 and 1868, and to closely conform in character to those of 

 1870 and 1871 ; and it was noted that 1860, like these two last- 

 mentioned years, was one of many sun spots. From that time 

 forward a correspondence between the general form of the 

 corona and the development of spots upon the sun has always 

 been looked for. The plate on p. 86, which is reproduced from 

 M. Backlund's Eeport on the Russian Expedition to Xovaya 

 Zemlya, 1896, represents the general form of the corona in the 

 eclipses from 1860 onward. The first column shows the coronae 

 of 1860, 1870, 1883 and 1893, at all of which dates the sun was 

 very largely spotted sun spots were at their maximum. The 

 second column shows the coronae in the years 1871, 1886, and 

 1896, when the solar activity was declining. It would have 

 been a more instructive comparison had the corona of 1874 

 been substituted for that of 1871, as the decline had scarcely 

 commenced in the earlier year. The third column gives the 

 years of minimum of 1867. 1878, and 1889, with a forecast for 

 1900. The last column represents a phase for which as yet we 

 have not much material the period of increasing solar activity. 

 It will be noted that the first three types are very distinctly 

 defined. 



MR. H. KEATLEY MOORE'S REPORT. 



IN the British Astronomical Association's Eclipse Expedition 

 to Xmway. 1896, our late President (Mr. N. E. Green) 

 organised a section for drawing the corona as seen by the 

 unaided eye. Twelve members placed themselves at his dis- 

 posal, and one or two meetings for practical preparation were 

 held. Mr. Green decided, after mature consideration, to draw 

 with white chalk upon purplish-blue paper, as best representing 

 with simple and easily managed materials the conjectured 



