Another way which is frequently adopted is to turn from the scene under examination to a contemporary picture in some great and well-known city such as Rome, and note what monarch is reigning there, or who are the consuls for the year; and when such data are discovered a glance at any good history will give the rest. Sometimes a date can be obtained by examining some public proclamation or some legal document; in fact in the times of which we are speaking the difficulty is easily surmounted.

The matter is by no means so simple, however, when we come to deal with periods much earlier than this—with a scene from early Egypt, Chaldæa, or China, or to go further back still, from Atlantis itself or any of its numerous colonies. A date can still be obtained easily enough from the mind of any educated man, but there is no longer any means of relating it to our own system of dates, since the man will be reckoning by eras of which we know nothing, or by the reigns of kings whose history is lost in the night of time.

Our methods, nevertheless, are not yet exhausted. It must be remembered that it is possible for the investigator to pass the records before him at any speed that he may desire—at the rate of a year in a second if he will, or even very much faster still. Now there are one or two events in ancient history whose dates have already been accurately fixed—as, for example, the sinking of Poseidonis in the year 9564 b.c. It is therefore obvious that if from the general appearance of the surroundings it seems probable that a picture seen is within measurable distance of one of these events, it can be related to that event by the simple process of running through the record rapidly, and counting the years between the two as they pass.

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, α Ursæ 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 Cæsar! 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.

It is quite true that some people have had glimpses of scenes from their past lives in dreams, but naturally these are usually fragmentary and unreliable. I had myself in earlier life an experience of this nature. Among my dreams I found that one was constantly recurring—a dream of a house with a portico over-looking a beautiful bay, not far from a hill on the top of which rose a graceful building. I knew that house perfectly, and was as familiar with the position of its rooms and the view from its door as I was with those of my home, in this present life. In those days I knew nothing about reincarnation, so that it seemed to me simply a curious coincidence that this dream should repeat itself so often; and it was not until some time after I had joined the Society that, when one who knew was showing me some pictures of my last incarnation, I discovered that this persistent dream had been in reality a partial recollection, and that the house which I knew so well was the one in which I was born more than two thousand years ago.

But although there are several cases on record in which some well-remembered scene has thus come through from one life to another, a considerable development of occult faculty is necessary before an investigator can definitely trace a line of incarnations, whether they be his own or another man's. This will be obvious if we remember the conditions of the problem which has to be worked out. To follow a person from this life to the one preceding it, it is necessary first of all to trace his present life backwards to his birth and then to follow up in reverse order the stages by which the Ego descended into incarnation.

This will obviously take us back eventually to the condition of the Ego upon the higher levels of the mental plane; so it will be seen that to perform this task effectually the investigator must be able to use the sense corresponding to that exalted level while awake in his physical body—in other words, his consciousness must be centred in the reincarnating Ego itself, and no longer in the lower personality. In that case, the memory of the Ego being aroused, his own past incarnations will be spread out before him like an open book, and he would be able, if he wished, to examine the conditions of another Ego upon that level and trace him backwards through the lower mental and astral lives which led up to it, until he came to the last physical death of that Ego, and through it to his previous life.