162 
Finally this report makes very evident the 
need for further investigation in regard to such 
important points as the best varieties of cane, 
and the possibility of their improvement by se- 
lection and crossing, the most suitable soil for 
sorghum, the effect of fertilizers on its growth 
and content of sugar, the methods of extract- 
ing the sugar from the cane, and the prevention 
of losses in the further treatment of the juice. 
In a word, while sugar can be made from sor- 
ghum, it yet remains to be seen how economi- 
cally it can be manufactured, and how complete- 
ly the great waste involved in the present crude 
processes can be avoided; and the committee 
closes its report by urging upon the U.S. de- 
partment of agriculture especially, the duty of 
continuing the investigations which have already 
yielded such important results. 
HANN’S CLIMATOLOGY. 
Handbuch der klimatologie. Von Dr. Jutius 
Hann. Stuttgart, J. Engelhorn, 1883. (Biblio- 
thek geographischer handbiicher.) 10+ 764 p. 
oe. 
THERE are many treatises upon the subject 
of climate. The larger number of these are 
devoted to the consideration of the special 
characteristics of the climate of some particu- 
lar country, and contain numerous statistics 
derived from meteorological observations, to- 
gether with a description of the prevailing 
weather conditions. A few discuss the subject 
from a broader stand-point, and take account 
of the general conditions which prevail over a 
large area, with their causes and modifications. 
The treatise before us, however, differs from its 
predecessors in its aim as well as in its execu- 
tion. It is designed to give a view of clima- 
tology as the result of certain forces which 
are at work in nature, and to investigate the 
result of the operations of these forces as they 
are exhibited in the climate of the world. Its 
author is the acknowledged head of meteoro- 
logical science in Austria, — one who has done 
much to place meteorology on a scientific basis, 
and who is especially qualified to speak with 
authority upon the subjects which he treats, 
on account of his well-known familiarity with 
the current work of other investigators, and 
his ability as a critic. It is to be expected 
that a work written by such an author will be 
comprehensive, thorough, and masterly, that 
it will indicate the present condition of the 
subject from a scientific stand-point, and be as 
accurate as the best data at hand can make it. 
All these conditions are fulfilled and abun- 
dantly satisfied in the work before us. 
SCIENCE. 
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[Vou. Tae 
The aim of the treatise is to present a com- — 
First the 
prehensive view of climatology. 
word is defined, its object specified, and the 
various climatic factors mentioned, briefly dis- — 
cussed, and illustrated. After this introduc- 
tion, which is, in fact, a concise treatise upon 
the subject of climatic statistics rather than a 
simple introduction, the author proceeds to 
treat the subject in two divisions, — general 
and special climatology. Under the former 
head are considered, 1°, ‘ solar climate,’ or that 
which would result directly from solar radia- 
tion; then, 2°, the modifications introduced by 
atmospheric and terrestrial conditions, result- 
ing in climate as actually existent. Under the 
latter head are considered the special climatic 
characteristics of different portions of the 
globe, with copious illustrations. In carrying 
out this plan, the author treats the various 
topics with conciseness but with singular clear- 
ness, and advances in logical progression with- 
out dwelling too much on the minor details, 
or retarding the course of thought by discuss- 
ing the many collateral subjects which are 
naturally suggested. Ina few instances, where 
a controverted subject is discussed in the text, 
an elaborate footnote is devoted to a defence 
of the author’s position, or a statement of the 
dissenting opinions of others; and several ap- 
pendices contain fuller explanations of the 
special topics touched upon in the main por- 
tion of the treatise. In this way the author 
preserves the unity of the work, and at the 
same time calls attention to important con- 
siderations to which he cannot give much space 
in the body of the treatise. ‘The work is not 
exhaustive: indeed, that would be impossible 
in so comprehensive a subject. In many cases 
it does not enter into the details of an inves- 
tigation, but gives the results obtained without 
discussing the methods of investigation em- 
ployed. 
At the outset the author carefully defines 
the word ‘ climatology,’ and shows the relation 
between climatology and meteorology. By 
climate is to be understood the average weather 
conditions of different places on the earth’s 
surface, together with the extent of the devia- 
tions from the average conditions. The clima- 
tologist, in treating the causes of climate, 
necessarily makes use of the laws which the 
meteorologist in his broader study of atmos- 
pheric phenomena has deduced, and, in turn, 
furnishes the latter with facts which he must — 
‘account for by the meteorological principles he 
has established. The two sciences are there- 
fore intimately connected ; and we may, if we — 
wish, regard climatology as a part of the 
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