MISCELLANEA. 
67 
As the silicic acid contains nearly twice as much oxygen as 
the aggregate of the bases, we have the result in the following 
formula. 
•Mg3 ^ 
z \ 
•Mn3 J 
This asbestos has then the same composition as pure augite, 
if we except the alumina, whilst the asbestos of Tarantaise, ana- 
lyzed by M. Bousdorf partakes of the composition of Hornblend, 
which, in reality, does not differ much from the former. It ap- 
pears therefore that asbestos is not a simple mineral, but only a 
form under which many present themselves, — Annalen der 
Physick, 
The application of M. Venetz^s hypothesis to the erratic pheno- 
mena of the North. — by M. de Charpentier. 
The last catastrophe which affected the northern hemisphere 
on any scale of importance, changed the climate to more cold 
and wet than it had partaken of before or since ; this tempera- 
ture was insufficient to melt completely the snows which existed 
to the N. of GO'' parallel of North latitude. The snows com- 
prised between the 60^ and 70° were transformed into glaciers, 
and above that they remained frozen. This glacier having accu- 
mulated to a considerable size, overwhelmed the north of Russia 
to Moscow, Prussia, Poland, the north of Germany, and perhaps 
even the eastern coasts of England. 
By these means the erratic deposits were transported and de- 
posited, and to this may be attributed the abrasion, aud groov- 
ings which are observed on the surface of the rocks. 
The osars are moraines, formed in part by the variations ex- 
perienced by the principal glacier in its retreat, and in part by 
the ice which remained on the summits long after the lowlands 
had become freed from snow. 
