The following angles were then calculated for each 10th degree of declination in turns, viz.:—­The height of the sun, etc., when above the horizon at each point of the compass. 2ndly, the bearing of the sun at each consecutive hour.  These points were dotted out; and, by joining the several sets of them, the drawing was made.

The broken lines which diverge in curves from P are hour lines; those which surround P in more or less complete ovals, are the paths of the sun and stars, for each 10th degree of declination; the prominent line running from E. round to W. being its path when on the Equator.

The diagram, when it is traced out for use, should have the names of the months written in coloured ink on either side of the south line at places corresponding to the declination of the sun during those months:  viz.:—­

January S. 23 degrees to S. 17 degrees
February S. 17 " S. 8
March S. 7 " N. 4
April N. 5 " N. 15
May N. 15 " N. 22
June N. 22 " N. 23
July N. 23 " N. 18
August N. 18 " N. 8
September N. 8 " S. 3
October S. 3 " S. 14
November S. 15 " S. 22
December S. 22 " S. 23

To use the card.—­Draw a broad pencil line, which may afterwards be rubbed out, corresponding to the date of travel, and there will be no further confusion.

Then, to know what o’clock it is, “span out” (see “Spanning”) roughly the altitude of the sun.  The point in the diagram where the altitude so obtained crosses the pencil mark, corresponds to the position of the sun.  The hour is then read off; and the compass bearings on the diagram are adjusted by holding it level, and turning it round until a line, drawn from its centre through the point in question, points towards the sun.  As to the moon or a star, if its declination be unknown, but its bearing and altitude being given, its declination and path may be found, and therefore the time since its rising or before its setting; a most useful piece of information to a traveller.  Watches break, and compasses cannot be used on horseback without stopping, and therefore a diagram of this description, of which any number of copies can be traced out, may be of use for rough purposes.

Other Signs of Direction.—­Bearings by the Growth of Trees.—­In exposed situations and near the sea, the growth of trees is rarely symmetrical; they betray by their bent heads and stunted branches the direction of the prevalent influences most adverse to their growth.  This direction is constant over wide districts in a flat country, but cannot be equally relied upon in a hilly one, where the mountains and valleys affect the conditions of shade and shelter, and deflect the course of the wind.