552 
tute so characteristic a feature of the high 
Alps: arm-chair-like recesses in the mountain 
slope, frequently arranged in groups all back- 
ing towards a central peak or an axial ridge 
and separated by sharply serrate spurs. Valley 
troughs are also considered, and these as well 
as the Kahre are referred to glacial erosion 
under conditions that are critically specified. 
Among many important conclusions are the 
following: The high Alps, rising above the 
snow-line of the glacial period, owe their form 
largely to the destructive processes of that 
time. Whole ranges, 100 kilometers long, ex- 
hibit sharp high-mountain forms, with corries 
and serrate spurs, although they bear no gla- 
ciers at present. If it had not been for the 
glacial period, these ranges would to-day have 
the rounded forms appropriate to mountains of 
middle height. During the most extensive gla- 
ciation, the Swiss ice-fields stood so high—even 
over the forelands towards the Jura—that 
they were above the level of the snow-line ; the 
slope of the snowy surface was gentle and the 
movement of the ice-streams in the larger val- 
leys must have been slow. The trough form 
that obtains in all the strongly glaciated valleys 
—with over-deepened floors and over-steepened 
walls—is due to erosion by glaciers of medium 
size, whose surface did not rise above the 
trough walls, but whose movement must have 
been relatively rapid because their surface 
slope was strong. Ice-scouring during maxi- 
mum glaciation reached far up the mountain 
slopes above the trough walls, but was without 
great influence on form. A level of extensive 
erosion is seen in the high Alps, coincident 
with the snow line of the glacial period; the 
peaks that rose above this level were actively 
consumed by weathering, while the surround- 
ing valleys were smothered in heavy but slow- 
moving ice. 
NEW ZEALAND. 
THE ninth volume of the Bibliothek der Lan- 
derkunde, entitled ‘ Neuseeland’ by R. von Len- 
denfeld (Berlin, Schall, 1900, 186 p., 24 pl. and 
fig., map), is a very attractive volume from 
which one may gain a clear impression of the 
country dealt with. Limiting this note to sec- 
tions of a physiographic nature, mention may 
SCIENCE. 
[N. S. Vou. XIII. No. 327. 
be made of Banks peninsula, a dissected vol- 
canic group, standing in front of the Canter- 
bury plains, with which it is connected by long 
tangential sand reefs. A tunnel cut through 
one of the volcanic slopes has disclosed 174 
different layers; lava, loose or compact, con- 
glomerate, and weathered soil. The Canter- 
bury plains, composed of recent fluviatile de-. 
posits brought from the mountainous back- 
ground, have a gentle slope seawards; the 
flooded rivers build up their surface with coarser 
deposits near the mountains and finer deposits 
near the shore; as their channels become 
clogged, the water deserts them for new 
courses, thus the whole surface is slowly ag- 
grading. The account of the fiords of the 
southwest coast mentions their numerous water- 
falls, but one must read between the lines to 
see that the falls leap forward from hanging 
valleys, such as now appear to be characteristic 
of strongly glaciated mountains. A striking 
example of such a valley seems to be shown 
in the plate of Mitre peak, Milford sound 
(fiord). The volume has a good index, but the 
pages are headed only with their numbers, in 
German fashion. The frontispiece of Mount 
Tasman and the Hochstetter glacier is remark- 
ably fine. 
W. M. Davis. 
CONTEMPORARY THERMODYNAMIC 
EFFICIENCIES. 
Tuis is the day of remarkable things in the 
field of heat-engine construction. The IJnch- 
dune, and a sister ship on the ‘Inch Line’ of 
a well-known British steamship company, has 
produced the horse-power-hour on 0.96 pound 
of coal and, for the time, holds the world’s 
record in steam-engine efficiency. This gives 
an efficiency, between the coal-pile and the 
point of transformation into power of the po- 
tential energy of the fuel, of almost precisely 
twenty per cent. 
The steam-turbine is produced in such per- 
fection of design and construction as to com- 
pete with the best of reciprocating engines of 
similar power and the report now appears in 
the German engineers’ Zeitschrift that Jacob- 
son, at Potschmiuhle, has tested a Laval Tur- 
bine which, rated at 300 horse-power, demands 
