310 
CAPTAIN L. DARWIN, DR. A. SCHUSTER, AND MR. E. W. MAUNDER 
4. Results of Second Test, or Photographs taken during the Partial Eclipse. 
The second of tlie two tests could be applied by taking photographs either during 
the eclipse, before or after totality, or sufficiently near first or last contact for the 
Moon to be still eclipsing the corona. I succeeded in taking over twenty photographs 
during these periods. Many of these, when developed, showed what I may describe 
as a false corona, that is, an increase of density near the Sun, including the part 
between the cusps, and therefore in front of the Moon. In none of these can the limb 
of the Moon be seen against the corona as a background. Besides subsequent exami¬ 
nation, I watched these photographs very carefully during development, without result. 
I mention this circumstance because they appear to have gone back considerably, so 
tliat, in several instances in which the air glare was clearly visible before fixing, it is 
now barely discernible. 
I have also searched for any trace of a remarkably large prominence in the place 
where I knew it should be found, but without result. This prominence w^as hardly, if 
at all, covered by the Moon after totality, that is, during the period in which nearly all 
my photographs were obtained. I’rominences are certainly more actinic than the corona, 
and we should therefore expect them to appear on the plate if the corona is obtain¬ 
able by this method. However, if the air glare increases much more rapidly in 
intensity than the corona does as the Sun is approached, this argument is not sound, 
as the prominenees might then be more overpowered by skylight than the outer parts 
of the corona would be. 
5. Photographs taken during Totality. 
It wdll be observed that the two experiments or tests just described w'ere made by 
taking photographs before and after the eclipse, and during the partial phases. But 
during totality the instrument w'as not idle. The following was the programme 
which I had laid down for myself during the 3 minutes 50 seconds available :— 
During the first minute a photograph was to be taken with the prismatic camera. 
After that, six plates were to be exposed with the coronagraph—four chloride plates 
with the same length of exposure as that given during Sun light, and two bromide 
plates with exposures of 5 and 10 seconds respectively. 
This programme could not be followed exactly. Immediately after I had com¬ 
menced exposing the prismatic camera, I looked up and found that a light cloud was 
drifting across the corona. The sky became clear again in about 50 seconds. I was 
anxious not to take any photographs with the coronagraph during the exposure of 
the prismatic camera, for fear of vibration; but, as nearly a minute had been lost, 
something had to be sacrificed, and I decided to take some of the photographs with the 
coronagraph before putting the cap on the jirlsmatic camera. I do not think that 
the work has suffered in consequence, and at all events I obtained all the plates I had 
allowed fur in my programme. 
