14 ; - REPORT—1852. 
all cases to have come to the conclusion that these apparent bodies were really at- 
tached to, and connected with, the sun, and were no less than masses of light-giving 
matter, 30,000 or 40,000 miles in length, and playing of course a most important 
part in the mystery of the nature and the source of solar light, and the whole 
cecohomy of that mighty orb. 
But if we are never to see these bodies but during the rare occasion of a solar 
eclipse, and then only for the too short space of three minutes, ages upon ages may 
pass away before we ascertain anything very precise upon the subject. In this case 
it becomes of the greatest importance to contrive some method of making the red 
prominences visible on ordinary occasions ; and a method having been proposed by 
Mr. J. Nasmyth of Manchester, which at least promised well, the author lost no 
time in putting it into execution. ; 
The method consisted in receiving the image of the sun and field of view, formed 
by 4 telescope in a dark room, on a white board, in which was a hole just large 
enough to let the sun pass through, and be absorbed on the inside of a black bag 
beyond ; the image of the field, and therefore of the sky in the immediate heigh- 
bourhood of the sun; could then be examined with the greatest nicety, and free from 
the prejudicial effect of the glating solar image; while any faint ray of light extend- 
ing from that luminary into the space beyond could be much more easily appreciated 
than before. But although the experiment was carefully tried on all the best days 
of last summer as well as the present, not the slightest appearance of red prominences 
could be detected. The author however would not presume to say that they did not 
therefore exist ; for although the experiment in itself was extremely successful, inas- 
much as during the very time that the sun was being received into the black bag the 
room itself was much darker than the atmosphere at the solar eclipse, yet the light- 
ness of the sky, by reason of the reflective power of the air outside the room, was so 
extreme, that nothing so faint as the red prominences are reputed to be, could well be 
seen on so bright a background. This is a difficulty which can only be got over by 
ascending to a great height in the atmosphere, and it would be well worth while to 
repeat the experiment on the top of a high mountain. 
Having given this experiment, founded on the opinions of observers, full trial, the 
author then thought himself justified in taking up an opposite idea, and supposing 
that the red prominences might be some spurious effects of diffraction of the sun’s 
light at the edge of lunar mountains. He therefore produced an artificial eclipse by 
introducing a small opake ball into the telescope, near the focus of the object-glass, 
when directed on the sun. The results were, that pink light, similar to that of the 
prominences, was thrown off from the edge of the eclipsing ball, in greater quantity as 
the polish of the surface was increased, and was broken up into more distinct portions 
the more irregular the surface.” Prominences most similar, nay, precisely like those 
of the eclipse, in shape and colour, were produced by an opal glass ball, scratched 
and cut on the edge with a diamond. 
There was however still the important failing, that the artificial prominences were 
connected with the eclipsing ball as a centre, and not with the sun, as in the case of 
the real prominences. In the latter instance, however, the sun’s rays fall on the 
moon in a parallel direction, while in the former they converge on the eclipsing 
ball. To arrive therefore more nearly at this particular, the author placed a large 
tin dise, with spherically curved tangential rim, on the top of the Nelson monument, 
and examined the appearance from below, when the sun was eclipsed behind the 
dise, with a small hand telescope. The result was that orange and red light were 
thrown off the edge; and in greater abundance, according to the greater proximity 
of the sun behind to any particular side of the disc, and also according to the greater 
purity of the atmosphere. This certainly seems to point out the great probability 
of a spurious origin for the red prominences at this surface of the lunar mountains ; 
but this experiment should also be tried on a high mountain, in an atmosphere a 
little more nearly approaching that of the moon in rarity and purity. 

