This being so, the approximate dates of the use of the three circles at the Hurlers can be derived. They are, with the above assumption:—
| B.C. | |||||
|---|---|---|---|---|---|
| Southern | circle aligning | Arcturus | over centre of | central circle | 1600 |
| Central | „ | „ | „ | N. circle | 1500 |
| Northern | „ | „ | „ | tumulus | 1300 |
The next step was to obtain, by means of a large circular protractor, more accurate readings of the Ordnance Map. This I could do, but the all important question of the angular height of the horizon remained. As it was impossible for me to leave London when the significance of the alignments was made out, I appealed to the authorities of the Royal Cornwall Polytechnic Society for aid in obtaining the necessary angles, and as a result, Captain J. S. Henderson, of Falmouth, an accomplished surveyor, volunteered his aid and shortly sent me the angular heights along some of the alignments, the means of eight readings obtained with a 6-inch theodolite, both verniers and reversed telescopes being employed. Other students of science besides myself will, I am sure, feel their indebtedness for such opportune help.
The combination of the large protractor and theodolite work gives the following final values. The difference between them and the provisional ones given above speaks volumes as to the necessity of a local study of the height of the horizon, a point I believe invariably neglected by archæologists.
FINAL VALUES.
| Arcturus from S. circle to central circle. | |
| Az. N. 11° 15′ E. | Hills, 3° 23′ 52″ high. |
| Dec. = 41° 38′ | Date, 2170 B.C. |
| Arcturus from central circle to N. circle. | |
| Az. N. 14° 18′ E. | Same hills. |
| Dec. = 41° 9′ | Date, 2090 B.C. |
| Arcturus from N. circle to Barrow. | |
| Az. N. 18° 14′ E. | Same hills. |
| Dec. = 40° 6′ | Date, 1900 B.C. |
Now before this evidence of star worship, so important if it can be depended on, could be accepted, it was necessary to make a special inquiry as to the existence of similar star observations in other places. Many have been found of which more in the sequel.
The next point which arose was that Arcturus used as a clock-star ([p. 108]) would serve as a warner for August. This necessitated another inquiry into the chief festivals in Cornwall: among these the August (Harvest) festival is one.
Another point to consider was whether there was any evidence of a local August festival. It happens that the Hurlers are in the parish of St. Cleer, and some of the other Arcturus sight-lines are in that of St. Just. Now, a local festival in old days was often associated with the local Saint. As most of the Cornish Saints are common to Cornwall and Brittany, I looked up the Calendar of the Annuaire of the Institut de France, and found that the days dedicated to SS. Justin and Claire are the 9th and 12th of August. It seems, then, that at the Hurlers it was really a question of a clock-star also used as a warning star for the August festival. I think we have at last, then, run to earth the origin of some of the northerly alignments referred to on [pages 36] and [43].
It will have been noted that the last sight-line on Arcturus was marked by a barrow. Captain Henderson inspected it and found it much ruined by explorers, remains of a chamber inside being visible.