The Druids, in laying down this design, that it might produce a magnificent effect suitable to so great and operose a work, studied the thing well. As this was to be a huge picture or representation of an animal, they purposed to follow nature’s drawing, as far as possible. A snake’s body has some variation in its thickness, as slenderer toward the neck, than at its middle. This the Druids imitated in making the avenue broader toward this southern entrance of _Abury_; and drawing it narrower as it approached _Overton-hill_. Again, when a snake is represented in its sinuous motion, the intervals of the stones sideways must have a variation, as set in the inner or the outer curve; so as to make them stand regularly opposite to one another: yet this necessarily makes some little difference in the intervals, and this too is properly regarded in the work. The whole length of this avenue consists of a hundred stones on each side, reaching from the _vallum_ of _Abury_ town, to the circular work on _Overton-hill_. Measuring the breadth of it in several places where I had an opportunity of two opposite stones being left, I found a difference; and the like by measuring the interval of stones sideways; yet there was the same proportion preserved between breadth and interval; which I found to be as two to three. So that here by _Abury_-town, in a part that represented the belly of the snake, the breadth of the avenue was 34 cubits, 56 feet and a half, and the intervals of the stones sideways 50 cubits, the proportion of two to three; twice 17 being 34, thrice 17 50. These 34 cubits take in the intire space of two intervals of the stones of the outer great circle of the temple of _Abury_ within the ditch, together with the intermediate stone, which is the entry of the avenue to the temple. A most ancient manner, a double door with a pillar in the middle. Such was that of the _Mosaick_ tabernacle: and such very often of our cathedrals. When we mount up _Overton-hill_, the avenue grows much narrower. And this observation help’d me in the discovery of the purport and design of the whole figure of the snake; and in the nature of the scheme thereof. Of which wonderful work we may well say with the poet; elsewhere, _Nec rapit immensos orbes per humum, neque tanto [Saxeus] in spiram tractu se colligit anguis._ Virg. Geor. 2.