Although some of the alignments already discovered are in all probability solstitial, the variation of the sun’s solstitial declination is so slow and takes place between such narrow limits that a most careful determination of the actual azimuths and of the angular heights of the various horizons must be made before any definite conclusion as to dates can be arrived at. The necessity for this care is illustrated in the paper on Stonehenge[126] communicated to the Royal Society by Mr. Penrose and myself in 1891, where, after taking the greatest precautions, the resulting date was in doubt to the amount of 200 years in either direction. So far Stonehenge is the only temple at which these observations have been made, so that for the other alignments contained in the following list no dates can yet be given. -----------+---------------+--------------+------------+---------+---- Monument. | Alignment. | Az. | Decl. | Season. |Date | | | (provi- | |B.C. | | | sional). | | -----------+---------------+--------------+------------+---------+---- Stonehenge |Direction of |N.49°34′18″ E.|23°54′30″ N.|Summer(R)|1680 |avenue | | | | | | | | | Boscawen- |Circ. to fine |N.53 30 0 E.|22 58 13 |Summer(R)| un |menhir | | | | |Circ. to Blind |N.54 30 0 E.|22 24 12 | „ | |Fiddler | | | | | | | | | Tregaseal |Circ. to row of|N.53 20 25 E.|22 53 26 |Summer(R)| |holed stones | | | | |Circ. to two |N.50 0 0 E.|24 7 0 | „ | |barrows 900′ | | | | |distant | | | | | | | | | Longstone |Mèn-an-tol to |S.50 30 0 W.|24 33 0 S.|Winter(S)| (Tregaseal)|Longstone | | | | | | | | | The |N. circ. to |S.50 50 0 E.|24 17 20 S.|Winter(S)| Hurlers |S.E. stone | | | | | | | | | Stanton |Gt. Circle to |N.51 0 0 E.|23 48 46 N.|Summer(R)| Drew |N.E. circle | | | | | | | | | Stenness |Circle to |N.39 30 0 E.|24 3 15 N.|Summer(R)| |Hindera Fiold | | | | |Barnstone to |N.41 16 0 E.| -- | „ |