SEPTEMBER 17, 1897. ] 
of it, forming a large swamp; further on it 
obstructs a valley on the south, forming 
Lake Merrill, and finally Kalama river 
falls over the end of the flow. Many large 
springs emerge from beneath the lava flows. 
MAARE OF THE EIFEL. 
Haxprass presents the results of sound- 
ings and temperature observations in the 
eight Hifel maare (Petermann’s Mitt., 
XLITI., 1897, 149-153 ; with more detail in 
Verh. Naturh. Vereins, Bonn, 1897). A 
ninth maar (Wanzenboden) is only two or 
three m. deep, and in part thickly occupied 
with reeds; the Hinkelsmaar and many other 
basins are now converted into dry meadows. 
Those which still hold water deepen from 
margin to center; at first gradually, then 
more rapidly with slopes of 20-30°, and 
again gently near the center. Only the 
Laacher See is large enough to have a well 
defined flat central floor. The Pulver maar 
is the deepest (74 m.) of all German lakes 
outside of the Alps. The shore lines ap- 
proach a circular outline, but the Meerfel- 
der maar is like a half moon, occupying 
only half of its circular basin. Much sta- 
tistical statement of fact with arithmetical 
comparison of the different maare is given. 
The life-history of the lakes is not directly 
considered. 
THE EASTERN ARCTIC SHA. 
SUPAN gives a review of Nansen’s polar 
expedition, from which the following notes 
on the eastern Arctic sea (the northern 
part of the ‘eastern hemisphere’) are 
taken (Petermann’s Mitt., VII., 1897, 158— 
163). Sheets of ice occupy much of the sur- 
face, continually drifted by currents and 
winds; now torn apart and opening water 
channels, now pressed together and forming 
walls and ridges. The latter reach heights 
of nine m., and offer the greatest obstacles 
to sled travelling. The remnants of former 
ridges drift about in berg-like masses with 
steep walls. The drift ice here is contrasted 
SCIENCE. 
439 
with the much thicker pack ice west of 
Greenland. The winter snow began melting 
in June, and the firm drift ice was not re- 
vealed till the end of summer. Its color is 
then a dirty brown, caused chiefly by min- 
eral dust. Fresh water pools are formed 
on the ice surface, surprisingly rich in mi- 
croscopic organisms. ‘The ice increased in 
thickness slowly through the winter to June, 
varied until August, and decreased to early 
winter. Thickening in summer is ascribed 
to freezing underneath of fresh water sup- 
plied by melting snow above. In early 
spring the ice was coldest, from —16° to 
—30°C. In summer it approached the 
melting point, and then became plastic, so 
that crushing took place without sound ; 
bending frequently replaced breaking. 
The discovery of the great depth of the 
Arctic, 3000-3900 met., where traversed by 
the Fram, is regarded as the most important 
geographical result of the expedition. Polar 
lands are, therefore, not to be expected. A 
sample of serial temperature soundings gives 
a surface layer 200 m. deep at —1°C.; a 
second layer, 660 m. thick, with mean tem- 
perature of +0°.22 C., and about 3000 m. 
of deep water with mean temperature of 
—0°.57C. The surface layer has least salt, 
and the intermediate layer most. The lat- 
ter is supplied from the North Atlantic, 
dipping beneath the Arctic surface layer 
because its density is determined by salin- 
ity rather than by temperature. 
W. M. Davis. 
HARVARD UNIVERSITY. 
CURRENT NOTES ON ANTHROPOLOGY. 
ARREST OF DEVELOPMENT IN HUMAN GROUPS. 
Ow this subject Professor Schrader has a 
curious article in the Revue Mensuelle of the 
Paris School of Anthropology. His conclu- 
sion is that the failure to advance or the 
actual retrogression of peoples and societies 
is a question of lack of adaptation to en- 
vironment. This is not new; indeed, it is 
