Nor is the vigour of this great body included only in its self, or circumferenced by its surface, but diffused at indeterminate distances through the air, water, and all bodies circumjacent. Exciting and impregnating Magnetical bodies within its surface or without it, and performing in a secret and invisible way what we evidently behold effected by the Loadstone. For these effluxions penetrate all bodies, and like the species of visible objects are ever ready in the medium, and lay hold on all bodies proportionate or capable of their action, those bodies likewise being of a congenerous nature, do readily receive the impressions of their motor; and if not fettered by their gravity, conform themselves to situations, wherein they best unite unto their Animator. And this will sufficiently appear from the observations that are to follow, which can no better way be made out then by this we speak of, the Magnetical vigour of the Earth. Now whether these effluviums do flye by striated Atoms and winding particles as _Renatus des Cartes_ conceiveth; or glide by streams attracted from either Pole and Hemisphere of the Earth unto the Equator, as Sir _Kenelm Digby_ excellently declareth, it takes not away this vertue of the Earth, but more distinctly sets down the gests and progress thereof, and are conceits of eminent use to salve Magnetical Phenomena's. [SN: _Apparencies observations._] And as in Astronomy those hypotheses though never so strange are best esteemed which best do salve apparencies; so surely in Philosophy those principles (though seeming monstrous) may with advantage be embraced, which best confirm experiment, and afford the readiest reason of observation.[SN: _The doctrine of effluxions acknowledged by the Author._] And truly the doctrine of effluxions, their penetrating natures, their invisible paths, and insuspected effects, are very considerable; for besides this Magnetical one of the Earth, several effusions there may be from divers other bodies, which invisibly act their parts at any time, and perhaps through any medium; a part of Philosophy but yet in discovery, and will, I fear, prove the last leaf to be turned over in the Book of Nature. [Sidenote: _Point to the North._] [Sidenote: _Point to the South._]