Procyon and Capella are both brighter than Spica, and they and Regulus are much brighter than the Pleiades. If one inclines to the Spica–Pleiades combination, it must be for other reasons. Independent dating from other possible alignments might offer us a way.
FIG. 16. The stone mortuary chamber of Wayland’s Smithy II, showing how rays from the brightest stars of the Southern Cross, when rising, fell diagonally across the chamber, grazing carefully shaped stones. (The blocking stone at the entrance, used to seal the tomb, is omitted. The places of missing stones are not indicated, but should be obvious.) The faces of the large stones at the ends of the transepts are likewise carefully placed so as to parallel the sides of the mound, and so would have aligned on alpha Crucis and Deneb before the mound covered them. If the arrangement indicated is not an illusion, then it is plain that religious conceptions were more important than astronomical observations. The upper plan covers the entire mound, and shows how beautifully the geometry of the chamber is related to that of the mound. The details hardly need to be spelled out.
The tomb begs to be considered as an artificial horizon for a view of the southern sky over the length of the barrow. The slope of the barrow was evidently small: judging by its dimensions, known and inferred, the angle set by it to an observer standing at ground level was a little under 2.36°, depending on its form. The massive central stones at the southern end would have been hidden to an observer at the north. Now it so happens that during the period in question the only reasonably bright star in anything approaching the required direction was the rising alpha Crucis, which has an extinction angle close to this figure. The star could have been seen over the chamber by an observer standing at the northeast corner along a line exactly parallel to the western long side. This was very precisely true around 3750 BC, assuming an extinction angle of 2.42°. (It has to be remembered that estimates of extinction angles are not absolute. To give an idea of potential uncertainties: bringing the angle down to 2.1° would in the present case advance the year by a century.) Alternatively, an observer standing at the northwest corner would have seen the same star rising at the same altitude, as if it were coming out of the large sarsen stone at the southwest corner. (This stone is unfortunately now missing, but was probably higher than the corresponding stone on the other side.)
There are interesting resemblances between old and new chambers: the internal measurements of the stone chamber were such as to bring in the ray from the rising alpha Crucis to the northeast corner of the chamber at this time. (With an estimated azimuth of 167.8° and an extinction angle of 2.35°, a year of 3640 BC is obtained.) There is, however, a new and quite unexpected alignment with the other main diagonal of the chamber, this time on the rising of beta Crucis.6 As in the other case the line is uncertain—they are estimates for standing observers rather than prone skeletons—but an azimuth of 150.1° and an extinction angle of 2.42° suggests a period around 3680 BC. The west ditch is just long enough to accommodate that same alignment over the crossing point in mid-chamber (see Fig. 16).
In sum, taking these additional dates into consideration inclines us to take the Spica–Pleiades combination, with its earlier date (3670 BC) and its more intuitively acceptable style of viewing at right-angles to near edges. Doing so, moreover, brings us to the middle of the radiocarbon range. All the dating is subject to error. For the time being, all too little is known of the ditch floor, but one thing at least seems probable, albeit based on only two sections: the floor falls gradually towards the north, as the ditch is pulled in to the tail of the barrow. This is surely how the angle of view was preserved, while lowering the height of the barrow. (Note that the principle of viewing at equal altitudes was generally implemented by having opposed sections at equal levels. It does not require level ditches, although they were indeed usually level.) When the ditch is completely excavated, the barrow’s form will be better known, but even now one can say—on the basis of ditch sections at the transept and at mid-mound—that the barrow was falling over this stretch at a gradient of about 4.3°. This gradient would have brought it down almost perfectly to ground level at its very tail, but perhaps the gradient was levelled out towards that end, so that the tail retained some height.
FIG. 17. The central area of the next figure.
This analysis has an important consequence for the sequence of building. For those who reject an astronomical interpretation, it makes little difference whether the mound preceded or followed the chamber. The precise astronomical alignment of the stones of the chamber, however, makes it seem certain that they were set up first, rather as the scaling posts for the older barrow had been.
Some people have seen the massive sarsens flanking the entrance to the surviving barrow as male to the right and female to the left. Alpha Crucis has a natural partner, beta Crucis, then slightly brighter, and to be seen on the side of the ‘male’ stones flanking the entrance. (One might equally say that it illuminated the ‘female’ side of the interior, and it would take a Jungian psychologist to decide on the more probable interpretation.) The two stars might well therefore have been regarded as male and female. Was gamma Crucis (magnitude 1.63) their child? The fourth star making up our cross is relatively feeble—but a second child, perhaps?7
FIG. 18. A general view of the planning of the mortuary house and its ditches at Wayland’s Smithy. For lettering, see the previous figure, and for a detail, see the next figure.
FIG. 19. A detail of the previous figure, showing the shape of the shallow pitched roof of the earliest mortuary house at Wayland’s Smithy. No attempt is made to show constructional details. Hatching is added simply to make the pitch (and the ridge) more evident.
Frame and Form at Wayland’s Smithy I
What has now emerged about potential uses of the later barrow at Wayland’s Smithy reflects back in an important way on the earlier phase of activity on the site. All the evidence of scale rules out the idea that observation of risings and settings of stars across the earlier structure was done by people standing at ground level, which would have required a higher central edifice than the later barrow. But what if Spica and the Pleiades were observed from the ditches, as it seems likely that they were with the second barrow?
An artificial barrier of wood or chalk or stone over the mortuary house would then have provided the horizon. Only two or three of the edges defined by what is known of the monument are acceptable for the purposes of observing the two stars, on the hypothesis that viewing was at right angles to the edges. They are the lines labelled KB and JA (or parallels to them) in Fig. 18, and they set azimuths (measured from north) of 73.2°, towards the rising of Spica, and 246.9°, towards the setting of the Pleiades, at an altitude and period as yet undetermined.
Note that whereas the second direction represents a shift of less than a degree from what was set by the later monument, the other direction differs from its later equivalent by three degrees. This alone should lead one to expect an appreciable time interval between the two monuments.
Applying exactly the same argument to the first phase of the barrow as that applied earlier to the second, perfectly consistent results are obtained only around the year 3940 BC. The two stars—the only bright stars with the property of being seen as stipulated over the right spread of centuries, would both have been observed at an altitude of 10.4°, when the Pleiades’ (Alcyone’s) declination was –5.59° and Spica’s was 18.58°.
Since Procyon, Capella and Regulus offered alternatives with the later mound,