[Illustration: FIG. 56.--Plan of the Mên-an-tol from Lukis, showing that it was an apparatus for observing the sunrise in May and August in one direction and the sunset in February and November in the other. Sun’s declination, 16° N. or S.] The azimuths suggest that theodolite measures may show that the Tregaseal stones might have been used in the same way; they, the Longstone and Lanyon Quoit, are in nearly the same straight line, the alignment, holed stones to Longstone and Lanyon Quoit, being N. 67° E., so that the May sunrise may have been noted in this way. [Illustration: _Photo. by Lady Lockyer._ FIG. 57.--The Mên-an-tol.] Several other monuments, _e.g._, Chûn Castle and Cromlech, are to be found in the immediate neighbourhood of the Tregaseal circle and the Longstone, but these will have to await further investigation as to their character and antiquity before any conclusions concerning their astronomical use can be deduced. [Illustration: FIG. 58.--The Mên-an-tol. Front view and section, from Lukis. ~Front view: D. LOOKING S.W., SCALE 1 INCH TO 1 FOOT.~ ~Section: SECTION OF D.~] Not only do we find in this neighbourhood the nest of holed stones to which I have referred, but the Mên-an-tol, the most famous of them all, in England at all events. This, then, is the place to say a few words about them. I have before stated my opinion that these stones, instead of being used as slaughter stones or posts at which to tie up the victim before sacrifice, or in any other similar employment, were really sighting stones to enable an alignment to be easily picked up. As such these were, of course, treated as sacred, and hence the folk-lore connected with them. This folk-lore seems to be most complete in the case of the famous stone of Odin at Stenness, so I condense Mr. Spence’s account of it. Children brought to the stone at Beltaine and Midsummer, after being carried sunwise round the holy well were passed through the hole as a protection against the powers of the evil one. Marriage ceremony consisted of joining hands through the hole, a vow held as sacred as the legal marriage of to-day. Pains in the head cured by inserting the head in the cavity, cure of palsy in children. Children and adults travelled many miles to secure relief in this way. At the Mên-an-tol the curative effects could only be obtained by crawling through the aperture, which is of considerable size. As a rule, however, the aperture is much more restricted. The general size of the holed stone and the position of the aperture in it may be well gathered from the fact that almost all of them have been used for gateposts, and are now to be seen fulfilling that function. In some cases the old special use can be inferred, but in others this is more difficult, as the stones have been shifted or slewed round, or the ancient monument to which the sighting stone was directed has disappeared.