This therefore shews the reason why they set their temples fronting the east, in all antiquity, and why the coves of our works look that way. As to the two temples at _Abury_, the northern and southern, included in the great circle, it should seem that the northern one had the preeminence, and was the more sacred of the two. As the cove was the _adytum_ of that temple, so the whole northern temple may be esteem’d as the _adytum_ of the whole work, the southern being as the body of it. _Solomon_’s temple, we know, consisted of three parts: the _adytum_, or _holy of holies_; the _holy place_, or _sanctuary_; the _porch_. By this means there is a conformity between it and _Abury_; and to _Stonehenge_ likewise, which has an elliptic _adytum_, a circular or outer part, and the _area_. Doubtless the different order of priests, and of religious offices, took up these different parts. And, if we may give our opinion, ’tis natural to think, that because the ring-stone is by the southern temple, there the sacrifices were offer’d and administer’d by the lesser orders of priests, around the _ambre_ or central pyramidal. The highest part of religion was to be perform’d by the archdruid and the upper order of priests before the magnificent cove of the northern temple, together with hymns, incense, musick, and the like. 5. In my account of _Stonehenge_ I suggested a surmise, that the Druids, in laying down these works of theirs, used a compass or magnetic instrument; whence I founded a conjecture concerning the time of building that temple, by observing the variation with a theodolite. As the variation in all the works about _Stonehenge_ is between six and seven degrees to the east of the north, I found it at _Abury_ to be about ten degrees the same way, and as precisely as possible. This will necessarily excite one’s attention, as there is less reason to suppose ’tis accidental. The whole work was manifestly design’d to be set on the cardinal points of the heavens, but they all vary one way, exactly the same quantity; and ’tis impossible to account for it in any wise, but that they us’d a magnetic instrument. This is the reason that the neck of the snake on _Overton-hill_ crosses the _Roman_ road running east and west, which would otherwise have been the ground-line of this work.