I have before pointed out (p. 149) that an avenue directed to the rising place of a star, if it is erected over undulating ground, cannot be straight. I may now mention another apparent paradox. If two avenues are directed to the rising place of the same star _at different times_, they cannot be parallel. It is not a little curious that absence of parallelism has been used against avenues having had an astronomical use! Both the Ordnance surveyors and Mr. Worth have shown the want of parallelism of the two avenues, and Mr. Worth has noted the kink in the southern one. The height of the horizon, as determined from my measures, is 3° 18′. The results of these inquiries, assuming the Pleiades to have been observed warning May morning, are as follows:-- Azimuth. Authority. N. Declination. Date B.C. ° ° ′ ″ N. 83·15 E. Worth 6 47 47 1710 82·30 Worth 7 16 20 1630 82·10 Ordnance 7 32 0 1580 80·40 Worth 8 26 0 1420 80·30 Ordnance 8 30 0 1400 To simplify matters we may deal with the Ordnance values and neglect the small change of direction in the southern avenue. We have, then, the two dates 1580 B.C. and 1420 B.C. for the two avenues. The argument for the Pleiades is strengthened by the fact that at Athens the Hecatompedon was oriented to these stars in 1495 B.C. according to Mr. Penrose’s determination of the azimuth. [Illustration: FIG. 43.--Plan, from the Ordnance Map, showing the avenues, circle and stones at Merrivale, with their azimuths.] Now this is not the first time I have referred to avenues in these notes. The azimuth of one at Stonehenge was used to fix the date at which sun worship went on there. That avenue, unlike the Dartmoor ones, was built of earth, and it is not alone. There is another nearly two miles long called the Cursus. So far, I have found no solstitial worship on Dartmoor, so there are no avenues parallel to the one at Stonehenge leading N.E. from the temple. But how about the other? _It is roughly parallel to the avenues at Merrivale, and I think, therefore, was, like them, used as a processional road, a via sacra, to watch the rising of the Pleiades._ [Illustration: FIG. 44.--Reprint of Ordnance Map showing that the Cursus at Stonehenge is nearly parallel to the Merrivale Avenue. The azimuth is 82° and not 84° as shown in the figure.] I said roughly parallel; its azimuth is about the same (N. 82° E. roughly); but the horizon is only about 1° high; it was therefore in use before those at Merrivale; the exact date of use must wait for theodolite values of the height of the horizon, but in the meantime we can see from the above estimates that the declination of the Pleiades was about N. 5° 28′ 30″ and the date of use 1950 B.C., that is some 300 years before the solstitial restoration.