350 REPORT—1883. 
should be restricted to the regions of the corona at corresponding distances 
from the sun’s limb... It is probable that the short exposure eclipse nega- 
tives will be found to admit of comparison with my plates better than 
those exposed for a longer time. 
Photographs of the sun have been taken on the days which follow :— 
April 2. : 2 . 1 plate June 6 ., 4 : . 3 plates 
Se ; : : 4 5S se 20". 4 ; . 1 plate 
aot ie ? : . 2plates | July 10 . : ‘ . 3 plates 
oe Zoe : : Ste Fy SO Let 2 : - Fy 5 oe 
May 23 . . é . 1 plate Aug. 8 . : ¢ nergy 
ek ame c s . 6 plates jraicie a 4 . Peres 
eee ; 4 5 uDe ies op eae 2 5 RANT, mesg 
Sept. 4 Ess 
All these plates show a more or less distinct coronal appearance about 
the sun. On some of the days an unfavourable wind brought here the 
London smoke, which greatly increased the sky illumination relatively to 
the coronal light which could reach the plate. On these days the photo- 
graphic action on the plates around the sun, though distinctly coronal in 
character, possesses less definiteness of form. I entertain the hope that 
it may be possible, by a careful comparison of all the plates, to gain some 
information in a general way of the amount, and possibly also of the 
character, of any large changes of form or of relative brightness which 
may have taken place in the corona or been due to its motion during the 
period covered by the observations. 
I stated in my paper read before the Royal Society that all I could 
hope to do in this climate and at the low elevation of my observatory, was 
to show a method by which, ‘under better conditions of climate, and 
especially at considerable elevations, the corona may be successfully 
photographed from day to day with a definiteness which would allow 
of the study of the changes which are doubtlessly always going on in it.’ 
‘Problems of the highest interest in the physics of our sun are connected, 
doubtless, with the varying forms which the coronal light is known to 
assume, but these would seem to admit of solution only on the condition 
of its being possible to study the corona continuously, and so to be able 
to confront its changes with the other variable phenomena which the sun 
presents. ‘‘ Unless some means be found,” says Professor C. A. Young, 
“for bringing out the structures round the sun which are hidden by the 
glare of our atmosphere, the progress of our knowledge must be very 
slow, for the corona is visible only about eight days in a century, in the 
aggregate, and then only over narrow stripes on the earth’s surface, and 
but from one to five minutes at a time by any one observer.” ’! 
P.S.—Messrs. Laurance and Woods, the observers sent out at the 
expense of the Government to photograph the eclipse of May last at 
Caroline Island, have compared Mr. Wesley’s drawings, and the original 
negatives from which they were made, with the photographs taken during 
the eclipse. Mr. Laurance, in a letter to Professor Stokes, dated 
September 14, 1883, says :— 
‘Dr. Huggins called upon Mr. Woods this morning and showed us 
the drawings Mr. Wesley has made of his coronas. He told us that he 
particularly did not wish to see our negatives, but that he would like us 
to compare his results with ours. We did so, and found that some of 
1 «The Sun,’ p. 289. 
