Moss grows best where there is continuous damp, therefore it prefers that side of a tree which affords the most suitable combination of exposure to damp winds and shelter from the sun.  When the winds do not differ materially in dampness, the north side of the forest trees are the most thickly covered with moss.

Bearings by the shape of Ant-hills.—­That most accurate observer, Pierre Huber, writes as follows concerning the nests of the yellow ants, which are abundantly to be found in the Swiss Alps and in some other mountainous countries.  It must be recollected, in reading his statement, that the chief occupation of ants is to move their eggs and larvae from one part of the nest to another, to ensure them a warm and equable temperature; therefore, it is reasonable to expect that the nests of ants should be built on a uniform principle as regards their shape and aspect.  Huber says “they serve as a compass to mountaineers when they are surrounded by thick mists, or have lost their way during the night; they do so in the following manner:—­The ant-hills (of the yellow ants), which are by far more numerous and more high in the mountains than anywhere else, are longer than they are broad, and are of a similar pattern in other respects.  Their direction is invariably from east to west.  Their highest point and their steepest side are turned towards the point of sunrise in the winter-time (au levant d’hiver), and they descend with a gradual slope in the opposite direction.  I have verified these experiences of the shepherds upon thousands of ant-hills, and have found a very small number of exceptions; these occurred only in the case where the ant-hills had been disturbed by men or animals.  The ant-hills do not maintain the constancy of their form in the lowlands, where they are more exposed to such accidents.”

Ripple-marks on Snow or Sand.—­The Siberians travel guided by the ripples in the snow, which run in a pretty fixed direction, owing to the prevalence of a particular wind.  The ripples in a desert of sand are equally good as guides; or the wind itself, if it happens to be blowing, especially to a person pushing through a tangled belt of forest.  Before leaving a well-known track, and striking out at night into the broad open plain, notice well which way the wind blows as regards the course you are about to pursue.

Flight of Birds.—­I have read somewhere that in the old days coasting sailors occasionally took pigeons with them, and when they had lost their bearings they let one fly, which it did at once to the land.

To follow a Track at Night.—­Where the track is well marked, showers of sparks, ably struck with a flint and steel, are sufficient to show it, without taking the pains of making a flame.

Smell of an Old Track.—­The earth of an old and well-trodden road has a perceptible smell, from the dung and trampling of animals passing over it, especially near to encampments.  It is usual at night, when a guide doubts whether or no he is in the track, to take up handfuls of dirt and smell it.  It is notorious that cattle can smell out a road.