On Finding the Way. 293
will always seem to have been disproportionately long compared to the latter. It is remarkable, on taking a long halfday's walk, and subsequently returning, after resting some hours, how long a time the earlier part of the return journey seems to occupy, and how rapidly different well-remembered points seem to succeed each other, as the traveller draws homewards. In this case, the same cause acts in opposite directions in the two journeys.
To Walk in a Straight Line through Forests.-Every man who has had frequent occasion to find his way from one place to another in a forest, can do so without straining his attention. Thus, in the account of Lord Milton's travels, we read of some North American Indians who were incapable of understanding the white man's difficulty in keeping a straight line; but no man who has not had practice can walk through trees in a straight line, even with the utmost circumspection.
After making several experiments, I think the explanation of the difficulty and the way of overcoming it are as follows -If a man walks on a level surface, guided by a single conspicuous mark, he is almost sure not to travel tow,-varrd's it in a straight line ; his muscular sense is not delicate enough to guard him from making small deviations. If, therefore, after walking some hundred yards towards a single mark, on ground that preserves his track, the traveller should turn round, he will probably be astonished to see how sinuous his course has been. However, if he take note of a second mark and endeavour to keep it strictly in a line with the, first, he will easily keep a perfectly straight course. But if he cannot find a second mark, it will not be difficult for him to use the tufts of grass, the stones, or the other accidents of the soil, in its place ; they. need not be precisely in the same line with the mark, but some may be on the right and some on the left of it, in which case, as he walks on, the perspective of their change of position will be symmetrical. Lastly, if he has not even one definite mark, but is walking among a throng of forest trees, he may learn to depend wholly on the symmetry of the changes of perspective of the trees as a guide to his path. He will keep his point of sight unchanged and will walk in its direction, and if he deviates from that direction,