Observe, in passing, that the first of these charts, wherein the stars of a constellation were indicated by Greek characters, appeared in 1603, at Augsburg, under the title of "Uranometria." Its author, Jean Bayer, an amateur astronomer, who died in 1660, conceived the idea of designating by the first letters of the Greek alphabet--α, β, γ, δ, and so on--the most noticeable stars. The animals bearing the names of the constellations are drawn in this map with very considerable care; but it requires, let us hasten to add, much imagination and good-will to recognise, in the form of a stellar group, the animal shown in the drawing. Thus far Ursa Major. The four stars of the quadriga, or chariot, have been employed to form the dorso-lumbar region of the animal; the three others define its tail; and, finally, twenty-four little stars, some of which are hardly visible to the naked eye, compose the head and paws of the celestial "plantigrade." As for Ursa Minor, it is impossible to distinguish it immediately when you are unaccustomed to surveying or examining the celestial vault. To detect its position, you require to be forewarned of it; to know, in the first place, that there exists in the vicinity of the Bear an exactly similar stellar group. The point of the tail--α in Ursa Minor--alone possesses a splendour comparable to that of the principal stars in Ursa Major. But how construct a figure with one star? The four other stars, two of which mark the anterior part of the animal's body, and two others the tail, properly so called, are only of the third magnitude: they are marked β, γ, δ, ε. Finally, the stars which define the posterior portion, marked ζ and η on Bayer's chart, are only of the fourth magnitude--in other words, are scarcely visible. The eye, to detect them, must be wholly free from any gleam of light. Many generations passed before they succeeded in discovering what a single individual solved during his brief career. All Homer's contemporaries, and, prior to these, tens of millions of mortals, had contemplated the sky, and yet none of them had detected the difference between Ursa Major and Ursa Minor. The distinction, therefore, is of a comparatively recent date; probably does not date back earlier than the sixth century before the Christian era. * * * * * Let us recall ourselves, now, to the question propounded. The first impression produced by the aspect of the sky during a beautiful winter night is, we repeat, that the number of the stars is infinite. This wholly spontaneous thought, which, to some extent, imposes itself on the mind long before the reason attempts any calculation, is, strange to say, both false and true. But how can a thought be both false and true? Nothing is easier than to explain the seeming contradiction. We shall return to it hereafter, after we have indulged in some indispensable digressions. ORION.