I have roughly determined this height from the 1-inch map in the case of the Barnstone-Maeshowe alignment. On the N.E. horizon are the Burrien Hills, four miles away, 600 feet high at the sunrise place, gradually ascending to the E., vertical angle = 1° 36′ 30″. The near alignment is on and over the centre of Maeshowe. Colonel Johnston, the Director-General of the Ordnance Survey, has informed me that the true azimuth of this bearing is N. 41° 16′ E., and in all probability it represents the place of sunrise as seen from the Barnstone when Maeshowe was erected. What is most required in Orkney now is that some one with a good 6-inch theodolite should observe the sun’s place of rising and the angular height of the hills at the next summer solstice in order to determine the date of the erection of Maeshowe. Mr. Spence and others made an attempt to determine this value with a sextant in 1899, but not from the Barnstone. In the absence of this observation we may use the diagram given on p. 121. With the height of hill previously given the sun should rise according to calculation at about the azimuth N. 41° 50′ E. The difference between the new and old azimuth then, on the assumption that az. N. 41° 16′ E. really represents an observation over Maeshowe, gives us the difference of date. Treating these figures then as we have done in the case of Stonehenge in Chapter VII, the result is as follows. The Barnhouse-Maeshowe line was established about 700 B.C., when the obliquity had a value of 23° 48′ according to Stockwell’s tables. (Fig. 40.) I confess the late date does not surprise me. The masonry of Maeshowe differs widely from that of other similar structures in that the sides of the gallery and chamber, instead of being composed of upright stones, are built in regular courses. I do not believe that the Maeshowe structure was built to observe a winter sunrise twenty days from the solstice, nor can I think it was set up at midsummer by someone who had only dealt with a high sun and a sea horizon, and imagined that the sunrise and sunset points were exactly opposite to each other. It was a priest’s house, and the alignment of the passage to the Barnstone was for the exchange of signals, probably by lights in Maeshowe itself. [Illustration: FIG. 40.--Variation of the Obliquity of the Ecliptic, 100 A.D.-4000 B.C. (Stockwell’s Values.) ~Horizontal axis: Years. From left: AD 0-BC 4000.~ ~Vertical axis: Obliquity. From bottom: 23.40-24.10.~] The Ordnance maps give no indication of stones, &c., by which the direction of the midsummer setting or the midwinter rising and setting might have been indicated from either the Maeshowe or the Barnstone. To sum up the solar alignments from the circle. We have the May sunrise marked by the top of Burrien Hill, from 600 to 700 feet high, Az. 59° 30′. We have the November sunset marked by a standing stone on the other side of the Loch of Stenness, Az. 53° 30′.