Davis and Wood.] 
368 
[Nov. 20, 
as related by similarity of structure, but also as comparable in re- 
gard to age. Moreover, some individuals raised to a considerable 
elevation in their } T outh, attain an intense development of all their 
features in maturity, and weaken only in old age ; others that have 
never gained much elevation have but a mild expression even at 
the strongest. 
3. Conception of systematic geography and geographic develop- 
ment. This conception of geography differs from that generally 
adopted in giving more attention than is commonly allowed to the 
development of geographic form, and in basing a classification on 
the sequence of forms assumed in the successive stages of the de- 
velopment of the type, as well as on the different structures of the 
types of various groups. It seems to be a rational extension of 
the study ; for nothing is better established than that the surface 
of the earth was not made in a final form as we see it, but has come 
to its present form through the action of natural processes, still 
in operation, such as are discussed in geology ; that the form result- 
ing from these natural processes depends on the structure that the 
processes work upon, on the time that the processes have been at 
work, and on the rate and opportunity for work as determined by 
altitude, climate, and other factors. It is certainly advisable to 
extend our conception of geography as fast as the various branches 
of knowledge applicable to it are extended ; meteorology has ad- 
vanced into a field of mathematical physics ; zoology turns on 
embryolog} 7 ; chemistry follows physics in utilizing atomic and 
molecular hypothesis to an extraordinary degree ; and if geog- 
raphy is to advance beyond narration and numeration, it must 
take all that it can gather from geology, and search for natural 
and genetic systems of classification and description. Geography 
comprehends a description of the surface of the earth ; and in or- 
der to carry the study out to its fullest use, it must draw on any 
source of information that aids and completes its descriptions. 
Physical geography includes discussion and explanation besides 
description, and must employ every method that increases the ra- 
tional understanding of its data. 
When one attempts the physical description of a political area, 
such as one of our states, it is like the work of a botanist in de- 
scribing the flora of a limited region. Plants of man}?' kinds will 
be found there naturally associated in an order quite unlike that 
given to them in a treatise on systematic botany ; but if good work 
