In our enquiry into the astronomy of the ancients we need not at all turn our minds to the difficult subject of the causes, or indeed even to the fact, of this slow movement of the earth’s axis, further than to realize fully that its effects have been to produce a slow but continuous change in the apparent position of the fixed stars, a change not in their position relatively to each other, but in their distances from the heavenly equator and its poles. The effort to fully realize these effects by means of careful calculations and measurements must prove to any but an astronomer a most arduous task; but, by aid of the mechanical contrivance called a “precessional globe,” much of the difficulty of the task may be overcome. The accompanying diagrams have been drawn from a precessional globe, which can be adjusted so as to show the position of the poles and equator amongst the fixed stars, at dates distant from each other by intervals of 538 years.[109] [109] 1800 A.D. is the date to which the globe in question originally refers; the intervals of 538 years can be reckoned backwards or forwards from this date. I have shown in continuous outline those constellations for whose first imagining it seemed to me as early a date might be claimed as that referred to in each diagram; all others are given in dotted outline. The strange figures of the “ancient constellations” are here drawn as they are represented on the globe; but the fixed stars which mark these figures for observers of the heavens, I have not ventured to indicate, as to do so would have required great accuracy of drawing and measurement. It is not for a moment to be contended that all the ancient constellations were imagined _exactly_ under the forms by which we have learnt to know them from classic representations, from the poem of Aratos, and from the star list of Ptolemy. Variants of many of the figures are to be met with in astronomical atlases and on the celestial globes in use to-day; and to establish the relative claims concerning the antiquity of these variant forms is a branch to itself of research. That these constellations have indeed been well denominated “ancient” is scarcely to be denied, and our only wonder, when studying the subject, must be, not that some differences are to be met with as to the exact form under which, at different dates and by different nations, these figures were delineated in the heavens, but rather the wonder must be that (as archæological research is always more and more clearly establishing) through many thousands of years, and by nations long and widely separated, the stars, which to an unaccustomed observer seem to be scattered in wild and random profusion on the sky, should have been divided into the same distinct groups, and thought of as representing the same mysterious beings.