DAVIS: THE HARVARD GEOGRAPHICAL MODELS. 
89 
The models are 24 by 18 inches in horizontal dimensions, and 
their greatest relief measures about two inches above their sea level. 
o 
Their scale may be taken as about an inch to a mile, and this will 
hold good for vertical as well as for horizontal measures. It is true 
that the slopes are strong in the mountainous area ; but while perhaps 
unusual in nature, they are not impossible. As here shown on 
reduced scale, some of the detail of form is lost; but when enlarged 
by lantern projection on a screen, it is all clearly portrayed, and the 
effect is very striking. 
In the construction of these ideal models, a guiding principle has 
been constantly borne in mind. A rational explanation must be 
given for every element of form. It is not necessary here to go 
elaborately into the many discussions that Mr. Curtis and I have 
held on the arrangement of ridges and valleys, peaks and passes, 
snow fields and glaciers, doabs and straths, headlands and deltas. 
Suffice it to say that close scrutiny has been given to every partic¬ 
ular, and that we believe the models to be substantially natural. 
Nearly every element of form has been justified by examination of 
photographs and large scale maps ; and the combination of these 
elements has been argued out so as to be reasonable and possible, 
althougdi not actual. Instead of describing; the models, the follow- 
ing paragraphs illustrate their teaching value by giving such an 
account of them as might be spoken by a teacher in a secondary 
school, while pointing to the models before a class of young scholars. 
First Model. Mountains bordering on the sea. Here the 
foot hills of a mountain range descend directly to the sea shore. 
Extensive snow fields are seen in the cold climate of the higher 
summits, supplying glaciers that creep down and melt away in 
milder temperatures of the valleys. ’ Streams fed by the glaciers 
and by many side branches on the valley slopes run rapidly down 
to their mouths at the sea shore. 
The rocks on the ridges weather slowly, and the waste is quickly 
washed down the steep slopes into the valleys, and carried along by 
the streams to the sea. The waves beat on the headlands, cutting 
cliffs in'their front. The larger rivers build deltas at their mouths, 
and here only is the sea bordered by low land. The depth and 
number of the valleys show that already much land waste has been 
carried into the sea. There it has been spread out by waves and 
currents. The sounding line shows the sea bottom to be much 
smoother than the land, deepening gradually for many miles off 
