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Southwest Prospect from Stonehenge
A. the barrow Ld. Pembroke open’d B.B. those I open’d C. Bushbarrow D. a cavity in the vallum.
In the orthographic plate, [Tab. XII.] we may see the strict geometry of the work of this outward circle, and the artful variation therefrom, in order to make the aperture of the grand entrance somewhat wider than the rest. Mr. Webb does not take notice of this particular; and he might have triumph’d in it. For ’tis no less than a Vitruvian rule, to relax the intercolumniation just in the middle of the portico, in the front of a temple, and over-against the door. He speaks of it in Lib. III. 2. when talking of the Eustyle ratio, the best for use, appearance and strength: he directs the intercolumniation to be of two diameters and ¼; but the middle intercolumniation of three diameters. By which means the approach to the door will be much more commodious, and nothing diminish’d of beauty in aspect. And this is the reality of the case before us.
But alas, our British priests knew nothing of Vitruvius; they deduc’d this knack from an authority much ancienter than him, viz., from pure natural reason, and good sense. Nor does this hurt the whole of the work. The aperture ought strictly to have been two cubits equal to the rest, but they advanc’d it to two cubits and a half. This only crowds the next intervals on each side a small matter nearer, the rest preserving their true distance quite round. And in the work itself, ’tis obvious enough to the naked eye. Again, there is another remarkable particular observ’d by our priests. Because the aperture of the principal entrance we are speaking of, is wider than the rest: they have made the impost over it thicker than the rest, and ’tis equally obvious to the naked eye. This was the more effectually to secure it from breaking. But this additional thickness they have put below. They were sensible it would have produc’d an ill effect at top, by breaking the line of that noble cincture. It must be own’d this was extremely well adjusted. And the breadth of the stone that hangs over head in this place is astonishing. See [Plate VII.] call’d a peep into the sanctum sanctorum. I had the greatest pleasure imaginable, in the year 1723, July, in being here for several days together, with the learned Heneage Lord Winchelsea. I have just reason to boast of that intimacy he indulg’d me in; and his memory must for ever be dear to me, for his noble qualities. My Lord and I were very careful in taking the measures of Stonehenge; and with great grief we observ’d, the stones here represented in that Plate, and [Tab. V.] the front view, to be much deviated forwards from their true perpendicular, and in the utmost danger of falling. ’Tis to be fear’d some indiscreet people have been digging about the great entrance, with ridiculous hopes of finding treasure, and loosen’d thereby the chalky foundation. We found by measure, that the upper edge of the impost overhangs no less than 2 foot 7 inches, which is very considerable in a height of 18. The whole breadth at the foundation is but 3 foot and a half. And this noble front is now chiefly kept up by the masonry of the mortaise and tenon of the imposts.
Thro’ the middle of the principal entrance, runs the principal line of the whole work; the diameter from north-east to south-west. This line cuts the middle of the altar, length of the cell, the entrance, the entrance into the court, and so runs down the middle of the avenue, to the bottom of the valley for almost 2000 feet together. This is very apparent to any one at first sight, and determines this for the only principal entrance of the temple. All the other intervals of the stones of the outer circle, have no preheminence in any respect. There is no such thing as three entrances, which Mr. Webb’s scheme suggests. He might as well have pretended there are 6, for so many points of his triangles meet in intervals, at the verge of the outer circle. Upon this line are all the principal centers that compose the work, it varies a small matter from true north-east.
The contrivance of our artificers in making mortaises and tenons, between the upright stones and the imposts is admirable, but so contrary to any practice of the Romans, that it alone is enough to disqualify their claim to the work. Much judgment and good sense is shewn in the management of them. The centers of the tenons are 2 cubits distant from each other, upon each upright. By this means there is 4 cubits distance from the center of the tenon of one stone, to the center of the tenon of its next neighbour, across the intervals, or in one impost. Divide the upper face of an upright into its 2 squares, the center of a tenon is in the center of that square. Divide the under face of an impost, into its 3 squares, the correspondent mortaises are in the centers of the two outermost squares, and this was the strict geometrical method us’d by the founders: so that the stones fitted, as soon as plac’d in their true situations. These tenons and mortaises of this outer circle are round, and fit one another very aptly. The tenons and mortaises, are 10 inches and a half in diameter, which is 3 palms, or half a cubit. They rather resemble half an egg, than an hemisphere. These most effectually keep both uprights and imposts from luxation, and they must have used great labour that threw them down. Sir Robert Sibbald speaks of a rocking stone in Ireland, contriv’d with mortaise and tenon like ours: of which Mr. Toland gives us an account, with other like, the works of the Druids.
The whole height of upright and impost is 10 cubits and a half. The uprights 9 cubits, the impost 1 cubit and a half, so that the impost is a 6th part of the height of the upright. If we measure on the outside, the collective breadth of two upright stones, and the interval between them, ’tis 10 cubits and a half equal to the whole height; and the interval is half the breadth of a stone, the thickness of a stone is half its breadth. That impost which lies over the grand entrance, we said, was deeper and longer than the rest. Abraham Sturges an architect, and myself measured it, in presence of Lord Winchelsea. Its middle length is 11 feet 10 inches, which is 6 cubits 4 palms; 2 foot 11 inches high, which is 1 cubit 4 palms. They have likewise added a little to its breadth, more than the rest, being 3 foot 9 inches, which is 2 cubits and a palm. N. B. The scale of my drawing is adapted for the inside of the circle, upon which the proportions in geometry are built: so that the outward breadths of the uprights and lengths of the imposts are somewhat more, than by the scale appears there. The intelligent reader knows this must be the consequence, in arks of a larger circle.
Stukeley delin.
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