ON FINDING THE WAY.
Recollection of a Path.--It is difficult to estimate, by recollection only, the true distances between different points in a road that has been once travelled over. There are many circumstances which may mislead, such as the accidental tedium of one part, or the pleasure of another; but besides these, there is always the fact, that, in a long day's journey, a man's faculties of observation are more fresh and active on starting than later in the day, when from the effect of weariness, even peculiar objects will fail to arrest his attention. Now, as a man's recollection of an interval of time is, as we all know, mainly derived from the number of impressions that his memory has received while it was passing, it follows that, so far as this cause alone is concerned, the earlier part of his day's journey will always seem to have been disproportionately long compared to the latter. It is remarkable, on taking a long half-day'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 towards 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, the want of symmetry in the change of perspective on either side of the point on which he wishes to walk, will warn him of his error. The appreciation of this optical effect grows easily into a habit. When the more distant view happens to be shut out, the traveller must regain his line under guidance similar to that by which a sailor steers who only looks at his compass at intervals--I mean by the aspect of the sky, the direction of the wind, and the appearance of the forest, when it has any peculiarity of growth dependent on direction. The chance of his judgment being erroneous to a small extent is the same on the right hand as on the left, consequently his errors tend to compensate each other. I wish some scientific traveller would rigidly test the powers of good bushmen and find their "probable" angular deviation from the true course under different circumstances. Their line should be given to them, and they should be told to make smokes at intervals. The position of these smokes could be easily mapped out by the traveller.
The art of walking in a straight line is possessed in an eminent degree by good ploughmen. They always look ahead, and let the plough take care of itself.
To find the way down a Hill-side.--If on arriving at the steep edge of a ridge, you have to take the caravan down into the plain, and it appears that a difficulty may arise in finding a good way for it; descend first yourself, as well as you can, and seek for a road as you climb back again. It is far more easy to succeed in doing this as you ascend, than as you descend: because when at the bottom of a hill, its bold bluffs and precipices face you, and you can at once see and avoid them: whereas at the top, these are precisely the parts that you overlook and cannot see.
Blind Paths.--Faintly-marked paths over grass (blind paths) are best seen from a distance.
Lost in a Fog.--Napoleon, when riding with his staff across a shallow arm of the Gulf of Suez, was caught in a fog: he utterly lost his way, and found himself in danger. He there-upon ordered his staff to ride from him, in radiating lines, in all directions, and that such of them as should find the water to become more shallow, should shout out.
Mirage.--When it is excessive, it is most bewildering: a man will often mistake a tuft of grass, or a tree, or other most dissimilar object, for his companion, or his horse, or game. An old traveller is rarely deceived by mirage. If he doubts, he can in many cases adopt the following hint given by Dr. Kane: "Refraction will baffle a novice, on the ice; but we have learned to baffle refraction. By sighting the suspected object with your rifle at rest, you soon detect motion."
Lost Path.--If you fairly lose your way in the dark, do not go on blundering hither and thither till you are exhausted; but make as comfortable bivouac as you can, and start at daybreak fresh on your search.
The bank of a watercourse, which is the best of clues, affords the worst of paths, and is quite unfit to be followed at night. The ground is always more broken in the neighbourhood of a river than far away from it; and the vegatation is more tangled. Explorers travel most easily by keeping far away from the banks of streams; because then they have fewer broad tributaries and deep ravines to cross.
If in the daytime you find that you have quite lost your way, set systematically to work to find it. At all event, do not make the matter doubly perplexing by wandering further. Mark the place very distinctly where you discover yourself at fault, that it may be the centre of your search. Be careful to ride in such places as will preserve your tracks. Break twigs if you are lost in a woodland: if in the open country, drag a stick to make a clear trail. Marks scratched on the ground to tell the hour and day that you passed by, will guide a relieving party. A great smoke is useful for the same purpose and is visible for a long distance. (See "Signals.")
A man who loses himself, especially in a desert, is sadly apt to find his presence of mind forsake him, the sense of desolation is so strange and overpowering; but he may console himself with the statistics of his chance of safety--viz., that travellers, though constantly losing their party, have hardly ever been known to perish unrelieved.
When the lost traveller is dead beat with fatigue, let him exert a strong control over himself, for if he gives way to terror, and wanders wildly about hither and thither, he will do no good and exhaust his vital powers much sooner. He should erect some signal--as conspicuous a one as he can--with something fluttering upon it, sit down in the shade, and, listening keenly for any sound of succour, bear his fate like a man. His ultimate safety is merely a question of time, for he is sure to be searched for; and, if he can keep alive for two or three days, he will, in all probability, be found and saved. (To relieve thirst, p. 223; hunger, p. 197)
Theory.--When you discover you are lost, ask yourself the following three questions: they comprise the ABC of the art of pathfinding, and I will therefore distinguish them by the letters A, B, and C respectively:--A. What is the least distance that I can with certainty specify, within which the caravan-path, the river, or the sea-shore, that I wish to regain, lies? B. What is the direction, in a vague general way, towards which the path or river runs, or the sea-coast tends? C. When I last left the path, did I turn to the left or to the right.
As regards A, calculate coolly how long you have been riding or walking, and at what pace, since you left your party; subtract for stoppages and well-recollected zigzags; allow a mile and a half per hour for the pace when you have been loitering on foot, and three and a half when you have been walking fast. Bear in mind that occasional running makes an almost inappreciable difference; and that a man is always much nearer to the lost path, than he is inclined to fear.
As regards B, if the man knows the course of the path to within eight points of the compass (or one-fourth of the whole horizon), it is a great gain; or even if he knows B to within twelve points, say 120 degrees, or one-third of the whole horizon, his knowledge is available. For instance, let us suppose a man's general idea of the run of the path to be, that it goes in a northerly and southerly direction: then if he is also positive that the path does not deviate more than to the N.E. on the one side of that direction, or to the N.W. on the other, he knows the direction to within eight points. Similarly he is sure to twelve points, if his limits, on either hand, are E.N.E. and W.N.W. respectively.
C requires no further explanation.
Now, if a man can answer all three questions, A, B, to within eight points of the compass, and C, he is four and a half times as well off as if he could only answer A; as will be seen by the following considerations. A knowledge of B in addition to A, is of only one-third the use that it would be if C also were known.
1. Let P (fig. 1) be the point where the traveller finds himself at fault, and let P D to be a distance within which the path certainly lies; then the circle, E D F, somewhere cuts the path, and the traveller starting from P must first go to D, and then make the entire circuit, D E H F D, before he has exhausted his search. This distance of P D + D E H F D = P D + 6 P D nearly, = 7 P D altogether, which gives the length of road that the man must be prepared to travel over who can answer no other than the question A. Of course, P D may cut the path, but I am speaking of the extreme distance which the lost man may have to travel.
Supposing that question B can be answered as well as question A, an that the direction of the line of road lies certainly within the points of the compass, P S and P R. Draw the circumscribing parallelogram, G L H E M, whose sides are respectively parallel to P S and P R. Join L M. By the conditions of this problem, the path must somewhere cut the circle E D F; and since L M cuts L H, which is a tangent to it, it is clear it must cut every path--such as a a, parallel to L H, or to P R--that cuts the circle. Similarly, the same line, L M, must cut every path parallel to P S, such as b b. Now if L M cuts every path that is parallel to either of the extreme directions, P R or P S, it is obvious that it must also cut every path that is parallel to an intermediate direction, such as c c, but
PL = PH/cos HPL = PD/cos 1/2 RPS;
The consequence of which is that P L exceeds P D by one-sixth, one-half as much again, or twice as much again, according as R P S = 60 degrees, 90 degrees degrees, or 140 degrees.
The traveller who can only answer the questions A and B, but not C, must be prepared to travel from P to L, and back again through P to M, a distance equal to 3 P L. If, however, he can answer the question C, he knows at once whether to travel towards L or towards M, and he has no return journey to fear. At the worst, he has simply to travel the distance P L.
The probable distance, as distinguished from the utmost possible distance that a man may have to travel in the three cases, can be calculated mathematically. It would be out of place here to give the working of the little problem, but I append the rough numerical results in a table.
The epitome of the whole is this:--1. If you can only answer the question A, you must seek for the lost path by the tedious circle plan; or, what is the same, and a more manageable way of setting to work, by travelling in an octagon, each side of which must be equal to four-fifths of P D. (See fig. 2.)
That is to say, look at your compass and start in any direction you please; we will say to the south, as represented in the drawing. Travel for a distance, P D; then supposing you have not crossed the path, turn at right angles, and start afresh--we will suppose your present direction to be west--travel for a distance 4/10 of P D, which will take you to 1; then turn to the N.W. and travel for a distance 8/10 of P D, which will take you to 2; then to the N. for a similar distance, which will take you to 3; and so on, till the octagon has been completed. If you know B to eight points, and not C, adopt the L M system; also, if you know A and C, and B to within thirteen points (out of the sixteen that form the semicircle), you may still adopt the L M system; but not otherwise. A rough diagram scratched on the ground with a stick would suffice to recall the above remarks to a traveller's recollection.