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Scientific Intelligence—Geology and Mineralogy. 383 
24th, there occurred another total eclipse of the moon, seen to great ad- 
vantage. Rarely do two central eclipses take place in one year; and 
it is, perhaps, equally seldom that two consecutive occultations are seen 
under such favourable circumstances. 
December.—This is both the coldest and the driest December which 
has come within the period of my observation. The mean temperature 
is 10°.369 under the average, and 13°.895, and 14°.169 respectively, under 
the temperature of the same month in 1842 and 1843. The evaporation 
exceeds the fall of rain by more than three-fold. The whole quantity 
of rain which fell from the 17th of November till the close of the year— 
44 days, only amounted to .405, or between a quarter and half an inch. 
12th, Lunar halo. 
Although we would decidedly discountenance the predictions of the 
so-called weather prophets, who profess to foretell atmospheric changes 
with a mathematical certainty ; yet it seems obvious, from an examina- 
tion of well-authenticated records kept over a long series of years, that 
wet and dry periods do succeed each other with tolerable regularity. 
The last three years have certainly exceeded the average in point of 
climate: and the experience of some of our oldest meteorologists would 
lead us to conclude, that this fine and dry period is not yet ended. 
J. F. MIuueEr. 
WHITEHAVEN, January 20th, 1845. 
SCIENTIFIC INTELLIGENCE. 
GEOLOGY AND MINERALOGY. 
1. Geognostical Structure of Magerde.—In the second part of Pro- 
fessor Keilhau’s Gaeca Norvegica there is a very interesting account of 
the geognosy of the island of Magerde in Finmark ; and we extract the 
following few facts, chiefly for the purpose of indicating the geognosti- 
cal constitution of the two most northern promontories in Europe. The 
largest portion of Magerde is composed of gneiss and mica-slate. The 
tract of gneiss lying farthest to the NW. of the island presents a rock 
which is petrographically identical with the oldest gneiss in Norway. 
The gneiss of Knivskjdl-Odden, the most northern promontory in 
Europe, is granitic, while the rock composing the tract of gneiss at the 
Kamoefjord, on the east side of the island, is partly the usual primitive 
gneiss, and partly a porphyritic gneiss, containing large crystals of fel- 
spar. The portion of gneiss occurring at Magerde Sound is of a less 
constant petrographical character ; and Von Buch says, that the cliffs in 
the Bay of Finyigen are so exceedingly black, that the observer has diffi- 
culty in persuading himself that they consist of gneiss. The rock at 
that locality is a small granular mixture of mica and a little quartz, the 
plates of mica being so small, that they can with difficulty be recognised. 
At another place in the same small tract of gneiss, the rock is more a 
granite than a gneiss or a mica-slate, and is a pretty coarse granular 
compound of greyish-yellow felspar and grey quartz, with so little mica 
that the slaty structure is by no means distinct. The central portion of 
Mageroe is composed of mica-slate, and contains two beds of white and 
grey granular limestone. This mica-slate district includes the North 
