516 
POPULAR SCIENCE REVIEW. 
twilight it was visible, but thinks that the very best atmospheric condi- 
tions are necessary to detect it. 
New Nebulae. — MM. Lassell and Marth have detected nearly 200 new 
nebulse with the great reflecting telescope now mounted at Malta. The 
last winter in that island was, however, unprecedentedly unfavourable for 
astronomical observations. 
Solar Envelope. — The discussion on the “ willow leaves,” or luminous 
isolated flakes which cover the sun’s surface, still continues. It would 
seem that the same appearances have been discovered by different ob- 
servers ; but having been examined with various magnifying powers and 
appliances, they have been described in independent terms by each, and 
only differ in language. Mr. Dawes considers the term “ willow-leaves ” 
as totally inapplicable to the shapes seen by him. A far less objectionable 
term he holds to be that of rice grains applied by Mr. Stone ; but even 
this conveys an idea of uniformity in shape and size, which they do not 
possess. He proposes that of granules , which expresses nothing in regard 
to their exact form or precise character. Recent observations have shown 
that their forms and sizes are so various as to defy any attempt to describe 
them by any comparison. The rarest of all forms Mr. Dawes found to be 
that of the long and narrow, and he could not find a single one which 
could be compared to a willow-leaf. One might be four or five times as 
large as another near it; one resembled a blunt and ill-shaped arrow- 
head, whilst another within 6" of it was an irregular trapezium with 
rounded corners. Mr. Dawes met with none of the interlacing seen in 
Mr. Nasmyth’s drawings, nor with the objects which he has depicted as 
the “exact form of those remarkable structural details.” It appears, 
however, that Mr. Nasmyth does not now regard them as of exact and 
uniform figure. Mr. Dawes is of opinion that the granules are larger as 
well as brighter on the bright portions of the sun ; and that in a mass of 
granules they are very nearly all of equal brilliance, faint and bright ones 
not being intermixed. The bright portions of the sun immediately sur- 
rounding the larger spots were found to be destitute of granulations, as 
also the faculse, which would seem to Mr. Dawes to prove that the com- 
motion which had produced those spots had heaped up in large masses the 
ordinary luminous photosphere of the sun. Mr. De la Rue maintains 
that Mr. Nasmyth has made a substantial discovery. Mr. Talmage was 
never able to see any of the appearances described by MM. Dawes and 
Nasmyth. Mr. Dunkin estimated that about three hundred of those 
granules lay in a space of 56” by 48". Mr. Dawes states that the ap- 
pearances recently discovered by the Greenwich observers are exactly the 
same as found by himself sixteen years ago, and after four years’ attentive 
observation, he came to the conclusion that these brilliant objects “were 
merely different conditions of the surface of the comparatively large 
luminous clouds themselves,” in respect to form, brilliancy, and elevation. 
An objection has been made that the small aperture of the solar eye-pieces 
used by Mr. Dawes probably interferes with the distinctness of the object 
viewed ; but it has been ascertained that at the centre of the field of view 
such is not the case. 
Photograph of Sun . — Although the progress of solar photography has 
