Still, if those years ran into thousands, as they might sometimes do, this plan would be insufferably tedious. In that case we are driven back upon the astronomical method. In consequence of the movement which is commonly called the precession of the equinoxes, though it might more accurately be described as a kind of second rotation of the earth, the angle between the equator and the ecliptic steadily but very slowly varies. Thus, after long intervals of time we find the pole of the earth no longer pointing towards the same spot in the apparent sphere of the heavens, or in other words, our pole-star is not, as at present, [Greek: a] Ursae Minoris, but some other celestial body; and from this position of the pole of the earth, which can easily be ascertained by careful observation of the night-sky of the picture under consideration, an approximate date can be calculated without difficulty. In estimating the date of occurrences which took place millions of years ago in earlier races, the period of a secondary rotation (or the precession of the equinoxes) is frequently used as a unit, but of course absolute accuracy is not usually required in such cases, round numbers being sufficient for all practical purposes in dealing with epochs so remote. The accurate reading of the records, whether of one's own past lives or those of others, must not, however, be thought of as an achievement possible to anyone without careful previous training. As has been already remarked, though occasional reflections may be had upon the astral plane, the power to use the mental sense is necessary before any reliable reading can be done. Indeed, to minimize the possibility of error, that sense ought to be fully at the command of the investigator while awake in the physical body; and to acquire that faculty needs years of ceaseless labour and rigid self-discipline. Many people seem to expect that as soon as they have signed their application and joined the Theosophical Society they will at once remember at least three or four of their past births; indeed, some of them promptly begin to imagine recollections and declare that in their last incarnation they were Mary Queen of Scots, Cleopatra, or Julius Caesar! Of course such extravagant claims simply bring discredit upon those who are so foolish as to make them but unfortunately some of that discredit is liable to be reflected, however unjustly, upon the Society to which they belong, so that a man who feels seething within him the conviction that he was Homer or Shakespeare would do well to pause and apply common-sense tests on the physical plane before publishing the news to the world.