Every stone is a block whose weight would try the most powerful machines. There are, in a word, scattered throughout the globe, masses, before which the word _materials_ seems to remain inexplicable, at the sight of which imagination is confounded, and that had to be endowed with a name as colossal as the things themselves. Besides which, these _immense rocking_ stones, called sometimes _routers_, placed upright on one of their sides as on a point, their equipoise being so perfect that the slightest touch is sufficient to set them in motion ... betray a most positive knowledge of statics. Reciprocal counter‐motion, surfaces, plane, convex and concave, in turn ... all this allies them to Cyclopean monuments, of which it can be said with good reason, repeating De la Vega, that “the demons seem to have worked on them more than men.”(772) For once we agree with our friends and foes, the Roman Catholics, and ask whether such prodigies of statics and equilibrium, with masses weighing millions of pounds, can be the work of Palæolithic _savages_, of cave‐men, taller than the average man in our century, yet ordinary mortals as we are? It is not our purpose to refer to the various traditions attached to the rocking stones. Still, it may be as well to remind the English reader of Giraldus Cambrensis, who speaks of such a stone on the Isle of Mona, which returned to its place, notwithstanding every effort to keep it elsewhere. At the time of the conquest of Ireland by Henry II, a Count Hugo Cestrensis, desiring to convince himself of the reality of the fact, tied the Mona stone to a far larger one and had them thrown into the sea. On the following morning it was found in its accustomed place. The learned William of Salisbury warrants the fact by testifying to its presence in the wall of a church where he had seen it in 1554. And this reminds one of what Pliny said of the stone left by the Argonauts at Cyzicum, which the Cyzicans had placed in the Prytaneum, “whence it _ran away several times_, and so they were forced to weight it with lead.”(773) Here we have immense stones stated by all antiquity to be “living, moving, speaking, and self‐ perambulating.” They were also capable, it seems, of making people run away, since they were called _routers_, from the word to “rout,” or “put to flight”; and Des Mousseaux shows them all to be prophetic stones, and sometimes called “_mad_ stones.”(774) The rocking stone is accepted by Science. But why did it rock? One must be blind not to see that this motion was one more means of divination, and that they were called for this very reason the “stones of truth.”(775)