These general remarks apply most particularly to _actio in distans_. It is objected that a cause cannot act where it is not, and where its power is not conveyed through a material medium. Now, this proposition is to be ranked among those which nothing but popular prejudice, incompleteness of conception, and imperfection of language cause to be received as axiomatic. We have pointed out that no material medium exists through which power can be conveyed; but as the objection is presented in popular terms and appeals to imagination, whilst our answer has no such advantage, it is very probable that the objection will keep its ground as long as men will be led by imagination more than by intellect. To avoid this danger, Faraday preferred to say that “the atom [primitive element] of matter is everywhere present,” and therefore can act everywhere. But by this answer the learned professor, while trying to avoid Scylla, struck against Charybdis. For, if the element of matter is everywhere present, then Westminster Abbey, for instance, is everywhere present; which cannot be true in the ordinary sense of the words. In fact, we are accustomed to say that a body is present, not in that place where its action is felt, but in that from which the direction of the action proceeds, and since such a direction proceeds from the centres of power, to these centres alone we refer when we point out the place occupied by a body. Prof. Faraday, on the contrary, refers to the active powers when he says that matter is everywhere present; for he considers the elements as consisting of power alone.(5) But this way of speaking is irreconcilable with the notions we have of determinate places, distances, etc., and creates a chaotic confusion in all our ideas of material things. He speaks more correctly in the passage which we have already mentioned, where he states that “each atom [element] extends, _so to say_, throughout the whole of the solar system, yet always retaining its own centre of force.” Here the words “so to say” tell us clearly that the author, having found no proper terms to express himself, makes use of a metaphor, and attributes _extension_ to the material elements in a sense which is not yet adopted in common use. He clearly wishes to say that “each element extends _virtually_ throughout space, though it _materially_ occupies only the central point from which its action is directed.” This latter answer is very good. But people are not likely to realize its full meaning; for in speaking of material substance men frequently confound that which belongs to it by reason of its matter with that which belongs to it by reason of its substantial form. It is evident, however, that if the substance had no matter, it would not mark out a point in space; it is, therefore, only on account of its matter that a substance is formally ubicated.