63 Natural-Historical Collections. 
It results from the combined observation of all the naturalists previously al- 
luded to, that the plant which occasions the coloration of snow, is also seen upon 
rocks, leaves, and other substances in cold countries: that it consists in a layer 
of white gelatinous matter stretched upon these surfaces, and supporting spherical | 
globules of a lively red, containing in their interior lesser globules of a yellow 
colour, which escape by. the rupture of the external membrane. 
The generic and specific characters of the Protococcus may then be given, as 
Dr. Greville has traced them, in his excellent memoir on this subject. 
Globuli aggregati, nudi, granulis farcti, in gelatina hyalina impositi. 
Protococcus nivalis, globulis exacté sphericis, minutissimis, vivide purpureis ;. 
gelatina pallida expansa. 
Hab. in nive alpina et polari, et supra lapides, folia, aliaque corpora in region- 
ibus frigidis Suecia, Norwegie, Scotia, &c. 
But it has been too hastily concluded, from the examination of this red snow, 
that this cryptogamous plant was the only cause of the coloration of snow and ice. 
It is well known that fresh water is often coloured, in a very intense manner, 
either by vegetables, or by little animals which inhabit it in great numbers. 
Mr. Decandolle published a curious memoir upon the red coloration of part of 
the waters of Lake Neufchatel, by a Conferva of the genus Oscillatoria, to which 
he gave the name of O. purpurea. (Mem. de la Soc. de Phys. et d’Hist. Nat. de 
Geneve. ) 
Little Entomostraca often give rise to a similar coloration of the water of 
shallows ; and Adolphe Brongniart saw the water of the canal of Gota in Sweden, 
near Berg, coloured for a considerable extent with a greyish green tint, by an in- 
finity of pale green globules, rendering the water very opaque; but he unfortu- 
nately had not the time to study their structure with minute attention. 
Sir Humphrey Davy has lately, in that interesting work * Salmonia, or Days 
of Fly Fishing,” advanced an opinion, that the colour of the ocean is probably m 
part due tothe two elementary principles, iodine and bromine, which its waters cer- 
tainly contain, and which result perhaps from the decomposition of marine vege- 
tation. These two substances dissolved in water give a yellow tint, and this tint 
mixed with the blue tint of pure water, may produce the green of the sea. Every 
thing affecting the latter colour would then be anomalous, and a fit subject for 
the research of naturalists. 
Mr. Scoresby has lately, in Professor Jameson’s Journal, published the re- 
sults of a particular examination of the tints of the water of polar seas, in which 
he states that the different tints of green, yellow, or red, are produced by little 
animals of the class of Radiata ; and the water, in freezing or in impregnating 
snow with its colouring matter, becomes a new source of coloration of snow and ice. 
Lastly, Mr Nicolson, a correspondent of the Magazine of Natural History, dif- 
fering with the opinion of former writers, describes the substance as scattered 
here and there in small masses, bearing some resemblance to powdered cochineal, 
. surrounded by a lighter shade, which was produced by the colouring matter being 
partly dissolved and diffused by the deliquescent snow. This substance, from 
the author’s garments becoming coloured with it, and from the snow on the 
mountains of higher elevation than the nests of little auk, (alca minor,) being 
perfectly white, he refers to the dung of this little bird, myriads of which were 
flying above Sowallick Point, on which the red snow Gece: 
This observation, though capable of adding to the causes of coloration already 
known, will not, from the facts of the extensive continuous tracts which are co- 
vered by it,—of its existence in countries and alpine districts where the little auk 
is not to be met with,—and from the researches of chemistry, and the faultless 
observations of Bauer, Hooker, Brown, and Greville, admit of any very extensive 
generalization, 
_Earthquakes.—In mentioning the occurrence of several shocks of an earthquake 
at Copenhagen, we cannot avoid alluding to the singular coincidence of several 
earthquakes having within a few months been felt in several places remote from 
from one another. The first of these was on the morning of the 18th of Septem- 
