30 W. Huggins—Photographing the Solar Corona 
the shutter was never less than half-an-inch in width, and often 
as much as an inch or even more, according to the sensitive- 
ness of the plates used. 
he most serious difficulty with which I have had to contend 
has been the absence of clear skies. On many days of bright 
sunshine the wind has been in a northerly direction, bringin 
here the smoke of London, which produces a whity condition 
of sky, through which it was obviously hopeless to expect the 
coronal light to show itself upon the plates. The few occasions 
of a better condition of sky were for the most part of short 
duration, and did not allow time for a large number of photo- 
graphs to be taken. 
uring the summer about three dozen photographs have 
been obtained, which show photographic action about the sun 
of a more or less coronal character. 
I placed these plates in the hands of Mr. Wesley, who has 
had very great experience in making drawings from the pho- 
tographs taken during several solar eclipses, with the request 
that he would make a drawing for each day on which sufficient 
photographs had been taken, combining the results of the dif- 
ferent photographs in one drawing. This was desirable, as, 
whenever a sufficient duration of sunshine permitted, photo- 
graphs were taken on silver chloride films as well as on silver 
bromide plates. Some photographs were taken with the sun 
screened by the brass disc, others without it; also photographs 
were taken with the sun in different positions of the field, As 
a rule, Mr. Wesley has introduced into his drawings those 
coronal features only which are common to all the plates taken 
on that da 
The apparatus is attached to the refractor of the equatorial 
in such a way that the direction of the length of the plate is in 
that of a parallel of declination; a line, therefore, across the 
plate, is in a direction north and south, and from the date of 
the photograph the angle of position of the sun’s axis can be 
found. On Mr. Wesley’s drawings the orientation is marked, 
as well as the position of the sun’s axis. 
Four drawings accompany this paper. On one of them 
(August 13) are seen defined rays. As these are present in 
three photographs—one in which the sun is in the middle of 
the field aod the shutter in use, a second in which the sun was 
nearly in the middle but the shutter remained open, and @ 
third with the sun near the margin of the field and screened 
by a disc—Mr. Wesley has put them in the drawing. In most 
of the negatives more structure than is shown in the drawings 
is suspected when the plates are carefully examined. 4 
I regretted greatly that on the sixth of May—the day of the 
solar eclipse-—the sky here was very unfavorable, 
