650 
POPULAR SCIENCE EEVIEAV. 
could be perceived unless the granules were discs of extreme thinness ; but 
no such structure could be imagined. Mr. Fletcher thinks that those phe- 
nomena were well known to Sir W. Herschel, and that they are fully 
described by him in the “Philosophical Transactions” of 1801. The 
drawings which accompany that paper seem to confirm that opinion. 
Mr. Brodie has likewise examined the surface and spots of the sun ; but 
his estimation of the dimensions of the granules scarcely coincides with 
that of Mr. Fletcher, as he thinks that some of them are about eight or ten 
seconds in length and some two seconds broad, and that they were lying in 
various directions. Mixed up with the “ rice-grains ” were the other forms 
which are always visible — those irregular rounded shapes of various sizes 
which produce the mottled appearance generally seen, the appearance of 
which has been compared by Mr. Brodie to a coarse shingle beach. He 
considers that those appearances are due to waves of photospheric cloud, 
which are not of equal elevation through their entire length, the vallej^s of 
the strata of the cloud intersecting each other very irregularly. He esti- 
mated the depth of the valleys of those cumuli clouds to be about 1,000 
miles ; but that is rather doubtful. The valleys, he considered, were darker than* 
the tops of the ridges, and the whole of the mottled surface of the sun bore 
some resemblance to the forms of the huge undulations of the mountains of the 
earth, as depicted in a good map, the elevated portions appearing as minute 
bright points, but much smaller than the ordinary faculce of the sun. The 
valleys, on the contrary, were noticed as sometimes speckled with black 
pores. The phenomena generally seen when a large spot makes its appear- 
ance have frequently been observed by Mr. Brodie ; viz., the shelving sides of 
the penumbra radiated with luminous streaks, which are frequently carried 
across the umbra, which is occasionally of a wispy form, like the cirro-stratus 
cloud of the earth ; and when this is the case, the perfectly black nucleus is 
always seen, though he has never been able to detect any bridge of luminous 
matter crossing the nucleus. On one occasion Mr. Brodie had an opportunity 
of observing the disruption of the umbra of a spot, which took place in the 
course of from three and a half to four hours. A tongue of luminous 
matter passed from one side of the spot to the other at the rate of 1,400 
miles per hour, and he forms the natural conclusion that it is to this mobility 
that the jagged edge of the penumbra is due, which has given rise to Mr. 
Nasmyth’s . “ willow haves, and their similarity at those parts to rough 
thatching. The umbra has occasionally been seen by him as containing 
isolated rounded portions of luminous matter, like icebergs floating on a 
black sea ; but those soon joined the edges of the penumbra. Mr. Brodie is 
unable to reconcile the actual appearance of the sun with the interlacing of 
the “ willow leaves,” which, he thinks, would produce a comparative evenness 
of surface which he has not yet observed. 
BOTANY. 
An Orchis mascula with double Flowers. — In the Journal of Botany for 
September, Mr. David Moore, of the Dublin Botanic Oarden, gives a descrip- 
tion of an Orchis mascula with double flowers. In the specimen which the 
