_Long vision_, during the clairvoyant state, or the recognition of objects greatly remote by the sensation each promotes, has its wonder much more in the _nature of the medium of space_ than in the familiar mental effect. The optically promoted sensation is proof that the external object, were it at the antipodes, is in mediate connection with not only the nervous fluid of the retina, but the brain. Long and ordinary vision have the same theory: in both states the same chromatic cerebral organ is excited by the nervous fluid; in both the nervous fluid is continuous from the brain to the external body; and in both the object perceived is the sensation of colour. That the eye-ball lenses are concerned in long and opaque, as in short vision, however in the two former, the eyes may be bandaged (to satisfy the desire of spectators, otherwise useless, if not worse,) is obvious, from the knowledge of form being connected with the sensation, as in every instance of optically-excited perception. By the passes, the nervous fluid is freed from the visual intercepting electric matter; which matter, like the colouring matter in stained glass, renders the continuity of the visual medium or fluid within the optic nerve impaired. To account for the phenomenon of much longer than ordinary vision, there is nothing in the mesmeric case to effect the difference, or refer to, but the de-electrised condition of the nervous fluid. From which it would seem that the visual line from the most remote object, is always as continuous to the brain as from one within arm's length before the face; and that the degree of cerebral exciting pressure on the longer line is rendered equally efficacious, _now_, that the electric impediment has been removed from the nervous fluid; hence, that the normal intermixed quantity of electric matter with the nervous fluid prevents us being clairvoyant at all times, is reasonable to conclude. _Opaque vision_, or the "seeing through opaque bodies," is not the absurdity so generally imagined when judged and reasoned on according to the true principles of visual perception: the facts of clairvoyance place the absurdity on the denier.