Geography in the United States. — Davis. ijr 
some mention of the occurrence of coal, because coal, now an 
element of inorganic environment, exerts a control over the dis- 
tribution and the industries of the population of Pennsylvania. 
But the coal of Pennsylvania might be treated with e(|ual ap- 
propriateness by a geologist, if its origin, its deformation and 
its erosion were considered as local elements in the history of 
the earth ; by a chemist, if its composition were the first object 
of attention ; by a botanist, if the ancient plants that produced 
the now inorganic coal-beds were studied. Furthermore, it 
would be eminently proper for the geologist to make some men- 
tion of the present uses to which coal is put ; or for the chem- 
ist and the botanist to tell something of the geological date 
when coal was formed, if by so doing the attention of the hear- 
er could be better gained and held, and if the problem at issue 
could thereby be made clearer and more serviceable. So the 
geographer is warranted in touching upon the composition, 
the origin, the exploitation of the Pennsylvania coal-beds, if by 
so doing he makes a more forcible presentation of his own 
problem; but if he weakens the presentation of his own prob- 
lem by the introduction of these unessential facts, still more if 
he presents these unessential facts as his prime interest, he goes 
too far. The point of all this is that students in many different 
sciences may have to consider in common certain aspects of the 
problems presented by the coal of Pennsylvania ; but that each 
student should consider Pennsylvania coal in the way that best 
serves his own subject. The scrutiny that I have urged would 
therefore be directed chiefly to excluding from consideration 
under geography the non-geographic relations of the many 
things that various sciences have to study in common, and to 
bringing forward in geography all the problems that are in- 
volved in the relations of the earth and its inhabitants. The 
things involved in the relations of earth and life are the com- 
mon property of many sciences, but the relations belong es- 
sentially to geography. It would be easy to point out topics in 
text-books and treatises, in the pages of geographical journals, 
and in lectures before geographical societies, that would not 
fall under any division of geography as here defined. In many 
such cases, however, the topics might without difficulty have 
given a sufficiently geographical turn, had it been so desired or 
intended ; the topics might have been presented from the geo- 
