332 New Cobalt Minerals. 
has recently busied himself without being able to find any 
ground, in all the depths of astronomy, for a greater change of 
annual heat than at the highest from 3° to 4°, and besides this 
change could only have come on very gradually, and could never 
have produced a sudden destruction of all organic nature. Still 
less do we find in the unequal temperature of space surrounding the 
earth, as assumed by Porsson, an explanation of the cause of these 
changes of heat and cold in terrestrial bodies; for, while a con- 
siderable increase in the coldness of the space in which the earth 
moves, would indeed produce a greater dissipation of the warmth 
of the earth, a lower temperature of the polar nights and more 
rapid loss of heat in our nights, it could scarcely be the means of 
freezing over all the bodies of water on its surface; and further- 
more, these changes could only after a long space of time exert 
an influence—and that a very gradual one—on the annual tem- 
perature and organic life. We are thence peremptorily referred 
to hypotheses to account for that change of temperature, but 
hypotheses are justly regarded as unproductive, and, although 
they played an important part in the geology of the last century, 
yet certainly physical inquirers, who do so much honor to our age 
as HH. Acassiz and Scuimerer, will again and again visit the 
smooth worn rocks before they resort to this extreme expedient, 
and repeat the question to themselves and others, whether this 
polishing could only be the effect of ice, or whether every possi- 
bility is cut off, that they may have been produced by water cur 
rents, as previous to their labors was generally believed. 
Il. On two new Cobalt Minerals, from Modum in Norway; 
by Hr. Prof. Dr. Wouter, (with a note by Prof. SueparD,) 
from a letter to Hr. Dr. Bium. 
We were too late with our examination of the new Modum 
Cobalt minerals, which you gave me last autumn. My analysis 
of them had been completed for some time, and I was about at- 
ranging the results, when I came across an acticle by ScHEERER 
of Modum, in the last number of Poggendorff’s Annals, where the 
same minerals are accurately and fully described.* ScHeeren’s 
i eee aii ty pepyty aee 
* The cobaltic a eee cat oe : ae Pd y ScHE ERER, as 0C- 
curring in two varieties ; one of which is crystallized and pata and as having 
