What the British astronomer-priests did, therefore, in the majority of cases was to set up their temples in a locality where the N.E. horizon was high, so that Arcturus rose and set over it and was invisible for only a short time, as shown in the diagram by the raised horizon _A′ B′_. The two lists following contain the names of the monuments where I suggest Arcturus was used as a clock-star. In the first, the angular elevation of the sky-line as seen from the circle in each case has been actually measured, and the date of the alignment is, therefore, fairly trustworthy; but in the second list the elevations have been estimated from the differences of contour shown on the one-inch Ordnance map, and the dates must be accepted as open to future revision. ARCTURUS AS A CLOCK-STAR. I. -------------+-------------------+---------------------------------+ | Position. | | Monument. +---------+---------+ Alignment. | | Lat. N. | Long. W.| | -------------+---------+---------+---------------------------------+ Tregaseal |50° 8′ 0″| 5°39′20″|Circ. to Carn Kenidjack | | | | | The Hurlers |50 31 0 | 4 27 20 |S. circ. over cent. circ. | | | |Cent. circ. over N. circ. | | | |N. circ. over N.E. barrow | | | | | Merrivale |50 33 15 | 4 2 30 |Circ. to remains of cromlech | | | |Direction of smaller avenue | | | | | Fernworthy |50 38 30 | 3 54 10 |Direction of Avenue | | | | | Stanton Drew |51 22 0 | 2 34 20 |Cent. of Gt. Circ. to Quoit | | | | | Fernworthy |50 38 30 | 3 54 10 |Direction of Avenue | | | | | Merry Maidens|50 3 40 | 5 35 25 |Circ. to stone in the road | | | | | Stanton Drew |51 22 0 | 2 34 20 |S.W. circ. to centre of Gt. Circ.| -------------+---------+---------+---------------------------------+ -------------+------------+------+-------+---- Monument. | Az. |Hills.| Decl. |Date | | | N. |B.C. -------------+------------+------+-------+---- Tregaseal |N. 12° 8′ E.| 4° 0′|42° 33′|2330 | | | | The Hurlers |N. 11 15 E.| 3 24 |41 38 |2170 |N. 14 18 E.| 3 24 |41 9 |2090 |N. 18 44 E.| 3 24 |40 6 |1900 | | | |