1864. | The Royal Astronomical Society. 281 
of Mr. Dawes is so well known in that particular field of research that 
any paper from him on the subject is heard with respect. The author 
commenced by pointing out the danger there was that observers, fur- 
nished with the more powerful telescopes now generally in use for 
solar inspection, would consider as new discoveries what was really only 
the revelation of superior telescopic power ; but which remained un- 
revealed in the diminished apertures formerly in use. This would be 
more likely the case where new names have been applied by a recent 
observer to phenomena long familiar to others, though previously un- 
named. Mr. Dawes has therefore considered it advisable to describe 
very minutely appearances which were observed long ago, that the 
new observer should know precisely what has already been seen in 
good instruments. Such an explanation was undoubtedly needed, as 
it is calculated to save much anxiety to the unpractised observer. 
With regard to the ‘ mottled’ appearance of the solar surfice, which 
is familiar to every observer, but in the description of which so many, 
and, to our minds, fanciful images have been used, Mr. Dawes makes 
the following remarks :—“ Examined with a large aperture, such as 6 
or 8 inches, it becomes evident that the surface is principally made up 
of luminous masses, imperfectly separated from each other by rows of 
minute dark dots,—the intervals between these dots being extremely 
small, and occupied by a substance decidedly less luminous than the 
general surface.” . . . “This gives the impression of a division between 
the luminous masses, especially with a comparatively low power, which, 
however, when best seen with high powers, is found to be never com- 
plete.” . . . “The masses thus incompletely separated are of almost 
every variety of irregular form ;—the rarest of all, perhaps, being that 
which is conveyed tomy mind by Mr. Nasmyth’s appellation of ‘ willow- 
leaves ; viz. long, narrow, and pointed.” * ... “Indeed the only situ- 
ation in which I have usually noticed them to assume anything like 
that shape, is in the immediate vicinity of considerable spots, on 
their penumbre, and frequently projecting beyond it irregularly for a 
small distance on to the wmbra. 
Mr. Dawes negatives the opinion, held by Sir John Herschel, amongst 
others, and mentioned in his Outlines, that the minute dark dots are 
ever in a state of change. He believes, from his own experience, that 
when observers have fancied they detected change, it was due to the 
influence of atmospheric action. There is, however, an exception to 
this state of quietude, “in the immediate vicinity of spots which are 
* At the next meeting of the Society, a letter from Mr. Nasmyth to Mr. 
Hodgson was read, in which the former gentleman made the plows remarks 
concerning the “ willow leaves” :— 
“The filaments in question are seen, and appear well defined, at the edges of 
the luminous surface where it overhangs the ‘ penumbra,’ as also in the details of 
the penumbra itself, and most especially are they seen clearly defined in the 
details of ‘the bridges,’ as I term those bright streaks which are so frequently 
seen stretching across from side to side over the dark spot. So far as I have yet 
had an opportunity of estimating their actual magnitude, their average length 
appears to be about 1,000 miles, the width about 100.’ 
“There appears no definite or symmetrical arrangement in the manner in 
which they are scattered over the surface of the sun; they appear to lie across 
each other in all possible’ variety of directions.” 
