FEBRUARY &, 1884 | 
science of meteorology, which takes into ac- 
count the phenomena included in the latter 
only in so far as they affect the well-being of 
living creatures on the earth. It is well to 
establish a definite position for climatology ; 
and the author is wise in restricting it to aver- 
age weather conditions, and deviations from 
the average, for these are the controlling in- 
fluences which determine the relations of any 
place to animal life. The important climatic 
factors are temperature, moisture, cloudiness, 
wind, atmospheric pressure, evaporation and 
the chemical composition of the air, mentioned 
nearly in the order of relative importance ; 
temperature, rainfall, and wind being usually 
given as the three essential factors. These 
factors are not independent, and are so mutual- 
ly connected (as, e.g., cloudiness and temper- 
ature) that they cannot be discussed separately. 
Atmospheric electricity is recognized as im- 
portant, but needing further study before it 
can be classed as a factor. It would seem as 
if a similar reason would have prevented the 
insertion of the composition of the air in the 
list of factors; for the relation of the chemical 
constituents in their varying proportions to 
animal life is confessedly obscure. In the dis- 
cussion of these factors, those special features 
with regard to each are mentioned which would 
be useful in representing statistically the 
climate of a place. Especial prominence is 
given to temperature statistics ; and eight dif- 
ferent subjects are named which deserve rep- 
resentation in tables, such as the monthly and 
annual means, magnitude of daily ranges, 
etc. An important omission in the tables 
usually given is pointed out ; viz.,some expres- 
sion for the rapidity of temperature changes. 
The author suggests two ways in which this 
can be done,—1°, by the difference between 
consecutive daily means, and, 2°, by the rapid- 
ity of changes in some adopted period of time. 
These and other suggestions can be profitably 
considered by those who have charge of the 
preparation of weather statistics: they should 
be presented in such a shape as to enable any 
one to readily obtain the facts as to the climate 
of any place for which he consults them. The 
statistics of Vienna are presented in illustration 
of the subject. 
The section devoted to general climatology 
is of special value. Quite properly, it begins 
with a discussion of climate as dependent upon 
the distribution of solar heat, and thus includes 
the results of investigations in solar radiation. 
Disregarding for the time the effect of the 
atmosphere, the distribution of solar heat is 
treated as dependent upon the sun’s altitude, 
SCIENCE. 
163 
the length of the day, and the distance between 
the earth and the sun. ‘The combined effect of 
these elements is seen in different latitudes and 
in the two hemispheres, and is the basis of actual 
climate. The effect of the atmosphere in modi- 
fying these results is next considered, and the 
subjects of atmospheric absorption, diffusion, 
and reflection treated. For the sake of com- 
parison, the relative effects on light, heat, and 
chemical power, are considered, though that 
relating to heat alone properly comes into con- 
sideration. The little knowledge which we 
possess on these subjects is the cause of the 
somewhat meagre presentation which the author 
gives. Coming finally to the further modifica- 
tions in the distribution of solar heat due to the 
earth itself, the characteristics of insular, con- 
tinental, and mountain climate are pointed out, 
and the effect of marine and aerial currents 
noted. In this way the author arrives at the 
actual climate which prevails over the earth, 
having started with its prime source, the sun. 
The discussion throughout is general, but is 
very suggestive of further study by the reader, 
in the different topics treated. The author 
quotes extensively from the works of others, 
and gives copious illustrations. It would be a 
great help to the student, however, if, as has 
been elsewhere suggested, references to the 
works themselves were given, in addition to 
the names of the authors, which are always 
carefully mentioned. This section could be 
expanded into a larger treatise, and may serve 
with advantage as the basis of extended re- 
search, or as a help to class instruction. 
The section devoted to special climatology 
occupies two-thirds of the whole work. After 
an introduction upon the division of the earth 
into climatic zones, the author considers the 
observed climate in each zone, quoting exten- 
sively from the publications which describe the 
prevailing conditions in each country, giving 
numerous tables, and summing up under each 
zone its general characteristics. In this sec- 
tion we have, therefore, a compendium of ac- 
cessible statistics covering the whole world, 
given in as much detail as the generous limits 
of the work will allow, and combined with care- 
fully prepared summaries. In order to judge 
of the excellence of this section, it is only 
necessary to note how thoroughly the different 
countries are treated, whether the selections 
made for illustration are typical or not, and 
whether the author has made use of the most 
relial‘le publications. In all these respects it 
will be found that the work before us excels. 
Thus, in describing the climate of North 
America, the author first gives a statement of 
