This change of cult may be due to the intrusion of a new tribe, but I am inclined to attribute it to a new view taken by the priests themselves due to a greater knowledge, among it being the determination, in Egypt, of the true length of the year which could be observed by the recurrence of the solstices, and of the intervals between the festivals reckoned in days.
However this may have been, all the old practices and superstitions were retained, only the time of year at which they took place was changed. As the change of cult was slow, in any one locality the celebrations would be continued at both times of the year, and for long both sets of holidays were retained.
Since I have shewn that the solstitial worship came last, traces of this, as a rule, would be most obvious in places where it eventually prevailed over the cult of the May year. In such places the absence of traces of the May festival would be no valid argument against its former prevalence. In other places, like Scotland, where the solstitial cult was apparently introduced late and was never prevalent, we should expect strong traces of the May worship, and, as a matter of fact, it is very evident in the folk lore and customs of Scotland; even the old May year quarter days are still maintained.
Between the years 2300 B.C. and 1600 B.C., whether we are dealing with the same race of immigrants or not, we pass from unhewn to worked stones. The method of this working and its results have been admirably shown to us by Prof. Gowland’s explorations at Stonehenge.
From the tables, given in Chap. XXVIII, it can be seen that, so far as the present evidence goes, there was a pretty definite time—about 2300 B.C.—of beginning the astronomical work at the chief monuments; Cornwall came first, Dartmoor was next.
Almost as marked as the simultaneous beginning are the dates of ending the observations, if we may judge of the time of ending by the fact that the precessional changes in the star places were no longer marked by the marking out of new sight lines.
The clock-star work was the first to go, about 1500 B.C. The May-warning stars followed pretty quickly.
We may say, then, that we have full evidence of astronomical activity of all kinds at the circles for a period of some 700 years.
What prevented its continuance on the old lines? It may have been that the invention of some other method of telling time by night had rendered the old methods of observation, and therefore the apparatus to carry them on, no longer necessary.
On the other hand, it may have been that some new race, less astronomically inclined, had swept over the land.