358 
POPULAE SCIENCE EEVIEW. 
examination of the new star. This seems all that has been done with it. The 
Astronomer Royal, however, saw enough with it to be convinced of the 
accuracy of the description, which compares (the appearance of the photo- 
sphere) with interlacing willow-leaves or rice-grains — a verdict which we 
can safely leave in the hands of those who come after him. 
Professor Grant, in his report, deals principally with the new determina- 
tion of the latitude of his observatory, and the efforts there made to dis- 
tribute true time. It is possible that the Town Council of Glasgow — hear 
it, ye Metropolitan Boards of Works and Unworks ! — will extend the applica- 
tion of the method of electric control to the turret clocks of all the city 
churches ! 
Saturn, though low, has lately been a most beautiful object, and is now be- 
ginning to give way to J upiter. Mr. Bishop has conferred a benefit upon 
astronomers by circulating an ephemeris of the ring system, and a table of the 
real dimensions of the planet, computed in English miles with Hansen’s solar 
parallax (^SlbS)), and Airy’s equatorial semi-diameter of the earth. This 
ephemeris, as also one of De Yico’s comet of short period, may be obtained 
by application at the Twickenham Observatory. 
BOTANY. 
The Colouring Matter of Sea-weeds . — An instructive memoir on the physio- 
logical purposes of the red pigment in the Florideae has been published in the 
Comptes Bendus, by M. Rosanoff, of Cherbourg. His experiments, which 
extended over several of the genera of this group, enabled him to form several 
important conclusions, a few of which we abstract as follows : — (1.) Like 
chlorophyll, the pigment displays protoplasmatic formations disposed upon a 
membranous layer of protoplasm. It is composed of granules, which may 
be elongated into curved spines, or may be spherical or band-like, and inflated 
at intervals. In the natural state they are homogeneous, but after they 
have been submitted to the action of water they become granular, spheroidal, 
and vesicular. They do not contain any appreciable quantity of starch, and 
are impregnated with red colouring matter. (2.) The pigment appears to be 
accumulated in the interior of the cells, especially when these are situated 
near the surface of the frond. (3.) With regard to the granules of starch and 
pigment particles, the latter form chains, which are broken by the former. In 
some cases the starch granule is surrounded by a number of pigment particles. 
But the starch granules are never covered by an envelope of coloured proto- 
plasm. (4.) The Floridese change colour on the spot on which they grow. At 
first they become brick-red, then they change to green, and finally they become 
completely discoloured. These are pathological phenomena which depend 
upon the action of light, of heat, and of the sea-water, which during lowtide 
becomes diluted by the rain. The first of these changes of colour depends 
upon the accumulation of the protoplasmic formations in the cellular juice ; 
the second is produced by an alteration in the constitution of the colouring 
matter ; and the third results from its complete destruction. 
The Movements of the Diatomacece . — The much-debated question as to 
whether the diatoms are animals or plants, appears to be more difficult 
