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At the end of the last chapter I referred to the Hor-shesu or followers, that is worshippers, of the Sun-god Horus. I shall have to refer to the traditions relating to them at a later stage, but it is well that I should state here that those personages who preceded the true historic period are considered by De Rougé and others to represent "le type de l'antiquité la plus reculée."

Let us for the moment accept the truth of the various traditions relating to them, and suppose that they left traces of their worship; what, in the light of the last chapter, should we expect to find? The thing most likely to remain would be ancient shrines in all probability serving for the foundation of nobler structures built in later times.

This brings us to the question as to the probabilities of temple-building generally in relation to the heavenly bodies; but before I deal with it, it is important to consider a view first put forward, I believe, by Vitruvius, and repeated by all since his time who have dealt with the question, that the temples were built purely and simply to face the Nile.[5]

The statement is so far from the truth that it is clear that those who have made it had not studied the larger temple-fields. Indeed, we have only to note the conditions at Karnak alone to determine whether there is any truth in the view that the temples face the river. We see at once that this idea cannot be true, because we have the chief temples facing in four directions, while the Nile flows only on one side.

Other archæologists who have endeavoured to investigate the orientations of these buildings have found that they practically face in all directions; the statement is that their arrangement is principally characterised by the want of it; they have been put down higgledy-piggledy; there has been a symmetrophobia, mitigated perhaps by a general desire that the temple should face the Nile. This view might be the true one, if stars were not observed as well as the sun.

With regard to all the temples of the ancient world, whether they are located in Egypt or elsewhere, we must never forget that if astronomy is concerned in them at all, we have to deal with the observations of the rising or setting of the heavenly bodies; whereas the modern astronomer cares little for these risings or settings, but deals only with them on the meridian.

The place of rising or setting would be connected with the temple by the direction of the temple's axis.

Now, the directions towards which the temples point are astronomically expressed by their "amplitudes"—that is, the distance in degrees from the east or west point of the horizon. For instance, a temple facing east would have an amplitude of zero from the east point. If we suppose a temple oriented to the north, it would have an amplitude of 90°; if half-way between the east and north, the amplitude would be 45° north of east, and so on. So that it is possible to express the amplitude of a temple in such a way that the temples in the same or different countries or localities, with the same or equivalent amplitudes, may be classified; and the more temples which can be thus brought together, the more likely is any law relating to their structure to come out.

Let us take this, then, as a general principle. Now how would it be carried out?

It becomes pretty obvious, when we consider the conditions of things in these early times, that the stars would be the objects which would first commend themselves to the attention of temple builders, for the reason that the movements and rising-and setting-places of the various planets by night, and of the sun by day, would appear to be so erratic, so long as the order of their movements was not known.

To go a step further. It is clear in the first place that no one would think of orienting a temple to the moon, as there is so little constancy about its path in the sky, and, therefore, in its place of rising or setting. If the temple caught it each month, the intervals between which this occurrence takes place would vary very considerably, and in early times would have been impossible to predict. Similarly it would not be worth while to orient temples to the planets. But when we come to the stars, the thing is different. A few years' observations would have appeared to demonstrate the absolute changelessness of the places of rising and setting of the same stars. It is true that this result would have been found to be erroneous when a long period of time had elapsed and when observation became more accurate; but for hundreds of years the stars would certainly appear to represent fixity, while the movements of sun, moon and planets would seem to be bound by no law.

Before, then, the yearly apparent movements of the sun had been fully made out, observations of a star rising or setting with the sun at some critical time of the agricultural cycle, say sowing-time or harvest, would be of the highest importance, and would secure the work being done at the right time of the—to the early peoples—still unformulated year.

If a star was chosen in or near the ecliptic, sooner or later the sunlight as well as the starlight would enter the temple, and the use of a solar temple might have thus been suggested even before the solstices or equinoxes had been thoroughly grasped.

There is no doubt that if we are justified in assuming that the stars were first observed, the next thing that would strike the early astronomers would be the regularity of the annual movement of the sun; the critical times of the sun's movements as related either to their agriculture, or their festivals, or to the year; the equinoxes and the solstices, would soon have revealed themselves to these early observers, if for no other reason than that they were connected in some way or other with some of the important conditions of their environment.

After a certain time, solar temples, if built at all, would be oriented either to the sun at some critical time of the agricultural—or religious—year, or to the solstices and equinoxes. But at first, until the fixity of the sun's yearly movements and especially the solstices and equinoxes had been recognised, it would have seemed as useless to direct a temple to the sun as to the moon. After a time, however, when the solstices and equinoxes had been made out, it would soon have been found that a temple once directed to the sun's rising place at harvest or sowing time, or at a solstice or an equinox, would continue for a long period to mark those critical points in the sun's yearly course; and when this yearly course had been finally made out it would soon be observed that the sun at any part of the agricultural year was as constant (indeed, as we now know, more constant) in its rising-and setting-place as a star.

But dealing with sun-worshippers, and endeavouring to think out what the earliest observers probably would try to do in the case of a solar temple, we see that, in all likelihood, they would orient it to observe the sun at one of the chief points in the year which could be best marked. I have said "which could be best marked," but how was this to be done? Evidently, if terrestrial things were to be assisted, the marking must have been by something exterrestrial, otherwise they would have been reasoning in a circle; and moreover we must take for granted that what was wanted was a warning of what was to be done.

Now, in the earliest times, as I have said, the constant movements of the stars would have stood out in strong contrast to the inconstant movements of the sun, and I think that there can be little doubt that the first fixing of any point in the year was by the rising or setting of some star at sunrise—or possibly sunset.

It is obvious that this might have gone on even before the solstices and equinoxes were recognised.

When this came about, then temples might have been directed to the sun at a solstice or an equinox.

Was it difficult to do this? Did it indicate that the people who built such temples were great astronomers? Nothing of the kind; nothing is more easy to determine than a solstice or an equinox.

Let us take the solstice first. We know that at the summer solstice the sun rises and sets furthest to the north, at the winter solstice furthest to the south. We have only from any point to set up a line of stakes before the time of the solstice, and then alter the line of them day by day as the sun gets further to the north or south, until no alteration is wanted. The solstice has been found.

There is another way of doing it. Take a vertical rod. Such a rod, which I may state is sometimes called a gnomon and used to measure time, may be used with another object: we may observe the length of the shadow cast by the sun when it is lowest at the winter solstice, and when it is highest; at these two positions of the sun obviously the lengths of the shadows thrown will be different. When the noon-sun is nearest overhead in the summer the length of the shadow will be least, when the sun is most removed from the zenith the shadow will be longest.

The day on which the shortest shadow is thrown at noon will define the summer solstice; when the shadow is longest we shall have the winter solstice.

This, in fact, was the method adopted by the Chinese to determine the solstices, and from it very early they found a value of the obliquity of the ecliptic.

It may be said that this is only a statement, and that the record has been falsified; some years ago anyone who was driven by facts to come to the conclusion that any very considerable antiquity was possible in these observations met with very great difficulty. But the shortest and the longest shadows recorded (1100 years B.C.) do not really represent the true lengths at present. If anyone had forged these observations he would state such lengths as people would find to-day or to-morrow, but the lengths given were different from those which would be found to-day. Laplace, who gave considerable attention to this matter, determined what the real obliquity was at that time, and proved that the record does represent an actual observation, and not one which had been made in later years.[6]

Next suppose an ancient Egyptian wished to determine the time of an equinox. We know from the Egyptian tombs that their stock-in-trade, so far as building went, was very considerable; they had squares, they had plumb-lines, they had scales, and all that sort of thing, just as we have. He would first of all make a platform quite flat; he could do that by means of the square or plumb-line; then he would get a ruler with pretty sharp edges (and such rulers are found in their tombs), and in the morning of any day he would direct this ruler to the position of the sun when it was rising, and he would from a given point draw a line towards the sun; he would do the same thing in the evening when the sun set; he would bisect the angle made by these two lines, and it would give him naturally a north and south line, and a right angle to this would give him east and west. So that from observations of the sun on any one day in the year he would practically be in a position to determine the points at which the sun would rise and set at the equinox—that is, the true east and west points.

Suppose that the sun is rising, let a rod throw a shadow; mark the position of the shadow; at sunset we again note where the shadow falls. If the sun rises exactly in the east and sets exactly in the west, those two shadows will be continuous, and we shall have made an observation at the absolute equinox. But suppose the sun not at the equinox, a line joining the ends of the shadows equally long before and after noon will be an east and west line.

It is true that there may be a slight error unless we are very careful about the time of the year at which we make the observations, because when the sun is exactly east or west at the time of rising or setting it changes its declination most quickly. So it is better to make the above observations of the sun nearer the solstices than the equinoxes, for the reason stated.[7]

We have now got so far. If the Egyptians worshipped the sun and built temples to it, they would be more likely to choose the times of the solstices and the equinoxes than any other after its annual movement had been made out.

Is it possible to bring any tests to bear to see whether they did this or not? Certainly: examine the temples which still remain, and where they have disappeared examine the temenos walls which still exist as mounds in many cases.

Suppose we take, to begin with, as before, that region of the earth's surface in the Nile valley with a latitude of about 26° N. The temples will have an amplitude of about 26° N. or S. if they have anything to do with the sun at the solstices. Any structures built to observe the sun will have an east and west aspect true if they have anything to do with the sun at the equinoxes. Dealing with a solstitial temple, the first thing to observe is the amplitude of the temple, which must depend upon the latitude in which it was wished to note the rising or setting of the sun at either of the solstices. If we take the latitude 26° N., which is very nearly the latitude of Thebes, the amplitude has to be 26° as stated above; so that a temple at Thebes having an amplitude of 26° would be very likely to have been oriented to the sun at the moment that it was as far from the equator as it could be—i.e., at the time of the longest day of the year—in which case we should be dealing with the summer or northern solstice; or of the shortest day of the year, if dealing with the winter or southern solstice.

As we deal with higher latitudes, we gradually increase the amplitude, until, if we go as far as the latitude of the North Cape, the sun at the summer solstice, as everybody knows, has no amplitude either at rising or setting, because it passes clear above the horizon altogether, and is seen at midnight.

These are the conditions which will define for us a solstitial solar temple. We see the amplitude of the temple must vary with the latitude of the place where it is erected.

But the temples directed to the sun at an equinox will be directed to an amplitude of 0: that is, they will point E. or W., and this will be the case in all latitudes.

The orientation of a temple directed to the sun at neither the solstices nor the equinoxes will have an amplitude less than the solstitial amplitude at the place.

As a matter of fact, as I shall show in the sequel, some of the temples recognised as temples of the sun in the inscriptions are of this latter class.