take his
knowledge from the thing, and to remember it by the mental picture of
the thing. In all education in Nature, whether the student is guided
by his own understanding or that of the teacher, a first and very
continuous aim should be to enforce the habit of recalling very
distinct images of all objects which it is desired to remember. To
this end the student should practise himself by looking intently upon
a landscape or any other object; then, turning away, he should try to
recall what he has beheld. After a moment the impression by the sight
should be repeated, and the study of the memory renewed. The writer
knows by his own experience that even in middle-aged people, where it
is hard to breed new habits, such deliberate training can greatly
increase the capacity of the memory for taking in and reproducing
images which are deemed of importance. Practice of this kind should
form a part of every naturalist's daily routine. After a certain time,
it need not be consciously done. The movements of thought and action
will, indeed, become as automatic as those which the trained fencer
makes with his foil.

Along with the habit of visualizing memories, and of storing them
without the use of words, the student should undertake to enlarge his
powers of conceiving spaces and directions as they exist in the field
about him. Among savages and animals below the grade of man, this
understanding of spacial relations is very clear and strong. It
enables the primitive man to find his way through the trackless
forest, and the carrier pigeon to recover his mate and dwelling place
from the distance of hundreds of miles away. In civilized men,
however, the habit of the home and street and the disuse of the
ancient freedom has dulled, and in some instances almost destroyed,
all sense of this shape of the external world. The best training to
recover this precious capacity will now be set forth.

The student should begin by drawing a map on a true scale, however
roughly the work may be done, of those features of the earth about him
with which he is necessarily most familiar. The task may well be begun
with his own dwelling or his schoolroom. Thence it may be extended so
as to include the plan of the neighbouring streets or fields. At
first, only directions and distances should be platted. After a time
to these indications should be added on the map lines indicating in a
general way contours or the lines formed by horizontal planes
inte