JANUARY 5, 1912] 
our native land should be even more sacred 
than its waters, and if necessary the constitu- 
tion should be amended to enable the Congress 
to pass laws protecting the soil as well as the 
waters of our common heritage. 
Frank W. VERY 
WESTWOOD, MASs., 
November 25, 1911 
SCIENTIFIC BOOKS 
Characteristics of Haisting Glaciers. By 
Wii™ Hersert Hosss. New York, The 
Maemillan Company. 1911. Pp. ix+ 301. 
The author tells us that the book consists 
of three articles, more or less amplified, which 
he has contributed to scientific magazines. 
This explains the general character of the 
book, which is divided into three parts; the 
first deals principally with glacial erosion; 
the second with the ice masses of the Arctics 
and the third with those of the Antarctics. 
The subject is treated in regard to some of its 
larger aspects, such as geographical distribu- 
tion, the general forms and the meteorological 
relations of the ice masses. The physical 
character of the ice which controls its move- 
ments, the relation of reservoir to dissipator, 
the formation of moraines and many other de- 
tails are absent, as might be expected from 
what has been said above. On the other hand, 
far more space is given to the question of 
erosion and to meteorological conditions than 
is usual in books about glaciers. 
In the first part, the subject of glacial ero- 
sion, both at the bottom of the valley and in 
the cirque wall, is considered. Here, for the 
first time, accounts of Matthes’s theory of 
nivation and Willard D. Johnson’s theory of 
bergschrund sapping are given to the general 
public. The author rejects Richter’s idea of 
sapping just above the level of the névé, be- 
cause it would produce a broad shelf, which 
has not been discovered; but he accepts John- 
son’s theory, though this method would also 
produce a shelf at a level only 150 or 200 feet 
lower. He has, however, presented convinc- 
ing evidence to show that the cirque is en- 
larged by sapping and that the forms with 
which we are familiar in glaciated mountains 
SCIENCE 
35 
are the result of the extension of cirques by 
glacier erosion. 
There are many ways of classifying glaciers, 
according to the characteristics one desires 
to emphasize. The author classifies glaciers 
in accordance with the amount of alimenta- 
tion, and brings out some interesting relation- 
ships of the different forms; but it seems that, 
in this matter, he has not put sufficient em- 
phasis upon underlying topography. 
The accounts of the Arctics and the Ant- 
areties are particularly interesting; the au- 
thor has evidently studied the reports of all 
the explorers and has brought them together 
in a very readable form and in such a way as 
to give an excellent general survey of those 
distant regions. He insists that there are 
very marked fundamental differences between 
the character of alimentation in the polar re- 
gions and in temperate zones. In the latter, 
the precipitation is due to moist winds being 
raised to cold altitudes by the mountains 
themselves and then precipitating their mois- 
ture in the form of snow. In the polar regions 
Professor Hobbs thinks that there are no sur- 
face air currents blowing across the great ice 
masses from the adjacent seas. It has been 
made out that over Greenland and over the 
Antarctics there are great regions of high 
barometer; and the reports of explorers show 
that they almost invariably encountered winds 
blowing off the surface of the ice, and when 
these winds attained a fair strength they car- 
ried with them many fine particles of snow 
which were swept along for considerable dis- 
tances. These outward air currents Professor 
Hobbs ascribes to the cooling and consequently 
increased density of the air by contact with 
the cold surfaces, followed by the air sliding 
off the great ice cap in all directions. This, of 
course, requires that the return currents 
should flow in at a higher altitude, and sink 
down upon the ice from above. These cur- 
rents, which bring but little moisture, are 
heated dynamically as they sink, melting and 
evaporating whatever ice spicules they may be 
carrying, and the vapor is again frozen as it 
approaches the ice surface. In this way he 
accounts for the falling snows under clear 
