Recourse has therefore been had to arguments of another kind. It has been pretended that, independently of the knowledge which these nations may have acquired, they have left monuments which bear a date fixed by the state of the heavens which they represent, and one that refers to a very remote antiquity. The zodiacs sculptured in two temples of Upper Egypt, are adduced as furnishing proofs perfectly demonstrative of this assertion. They present the same figures of the zodiacal constellations as are employed at the present day, but distributed in a manner peculiar to themselves. The state of the heavens at the period when these monuments were delineated, is imagined to have been represented by this distribution, and it has been thought that it would be possible from it to infer the precise period at which the edifices containing them were erected[212].

But to arrive at the high antiquity which is supposed to be deducible from this, it must, in the first place, be supposed, that their division has a determinate relation to a certain state of the heavens, dependent upon the precession of the equinoxes, which causes the colures to make the tour of the zodiac in 26,000 years; that it indicated, for example, the position of the solstitial point; and, secondly, that the state of the heavens represented was precisely that which took place at the period when the monument was erected,—two suppositions which themselves, as is evident, suppose a great number of others.

In point of fact, are the figures of these zodiacs the constellations,—the true groups of stars which at present bear the same names, or merely what astronomers call signs, that is to say, divisions of the zodiac proceeding from one of the colures, whatever place this colure occupies? Is the point at which these zodiacs have been divided into two bands, necessarily that of a solstice? Is the division of the side next the entrance, necessarily that of the summer solstice? Does this division indicate, even in general, a phenomenon dependent upon the precession of the equinoxes? Does it not refer to some period the rotation of which would be less; for example, to the moment of the tropical year when such or such sacred years of the Egyptians commenced, which, being shorter than the true tropical year by nearly six hours, would make the tour of the zodiac in 1508 years? Lastly, whatever signification it may have had, has it been intended by it to mark the time when the zodiac was sculptured, or that when the temple was built? Has not the object been to record a previous state of the heavens at some period which was interesting in a religious point of view, whether it had been actually observed, or inferred from a retrograde calculation?

From the mere announcement of such questions, it will be perceived how complicated they necessarily are, how much subject to controversy any solution that might be adopted on this subject would be, and how little qualified to serve as a solid proof, for the solution of another problem, such as the antiquity of the Egyptian nation. And it may be said, with regard to those who have attempted to infer a date from these data, that there have arisen as many opinions as there have been authors.

The learned astronomer Mr Burkhard, from a first examination, judged that, at Dendera, the solstice is marked by the Lion; which would make it two signs less remote than at the present day, and the temple at least 4000 years old[213]. He gave, at the same time an antiquity of 7000 years to that of Esne, although it is not known how he had purposed to reconcile these numbers with what we know of the precession of the equinoxes. The late M. Lalande, seeing that the Cancer was repeated on the two bands, imagined that the solstice passed to the middle of that constellation; but as this was the case also in the sphere of Eudoxus, he concluded that some Grecian artist might have represented this sphere on the ceiling of an Egyptian temple, without knowing that it represented a state of the heavens which no longer existed[214]. This, as is seen, was a conclusion very different from that of Mr Burkhard. Dupuis was the first who thought it necessary to search for proofs of the idea, in some measure confidently adopted, that it was the solstice that was denoted. He found them, with reference to the great zodiac of Dendera, in the globe on the top of the pyramid, and in several emblems placed near different signs, and which he imagined, sometimes according to the opinion of ancient authors, such as Plutarch, Horus Apollo, or Clement of Alexandria, sometimes according to his own conjectures, ought to be regarded as representing phenomena which had been really those of the seasons affected at each sign. As for the rest, he maintained that this state of the heavens affords the date of the monument, and that it is the original, and not a copy, of the sphere of Eudoxus, that was represented at Dendera, which would refer it to a period of 1468 years before Christ, or to the reign of Sesostris. The number of nineteen boats, however, placed under each band, furnished him with the idea that the solstice might probably have been at the nineteenth degree of the sign, which would make it 288 years older[215].

Mr Hamilton[216] having remarked, that, at Dendera, the Scarabæus belonging to the side of the ascending signs is smaller than that of the other side, an English author[217] has concluded from this that the solstice may have been nearer its actual point than the middle of the Cancer, which would carry us back to a period of 1000 or 1200 years before Christ.

The late M. Nouet, judging that the globe, the rays, and the horned head, or head of Isis, represent the heliacal rising of Sirius, supposed that it was intended to mark an epoch of the Sothian period, but that it was intended to mark it by the place which the solstice occupied. Now, in the last but one of these periods, that which elapsed between 2782 and 1322 before Christ, the solstice had passed from 30° 48′ of the constellation of the Lion to 13° 34′ of Cancer. At the middle of this period, it was therefore at 23° 34′ of cancer. The heliacal rising of Sirius happened then some days after the solstice; and this is nearly what has been indicated, according to M. Nouet, by the repetition of the Scarabæus, and by the figure of Sirius with the rays of the sun placed at the commencement of the band to the right. Calculating upon this basis, he concludes that the temple of Dendera was built 2052 years before Christ, and that of Esne 4600[218].

All these calculations, even admitting that the division marks the solstice, would still be susceptible of many modifications; and, at first, it appears that their authors have supposed the constellations all of thirty degrees like the signs, and have not reflected that it is far from being the case that they are thus equal, at least as they are represented at the present day, and as the Greeks have transmitted them to us. In reality, the solstice, which is at present on this side of the first stars of the constellation of Gemini, could only have left the first stars of the constellation of Cancer forty-five years before Christ, and had left the constellation of Leo only 1260 years before the same era.

My distinguished and learned colleague, M. Delambre, has favoured me with the following table and remarks, which illustrate what has been above said.

TABLE of the Extent of the Zodiacal Constellations, as they are designed upon our Globes, and of the Times required by the Colures to traverse them.