628. When the rays of the setting sun fall upon the glass of windows, we see one portion reflected with great effulgence, yet another goes through the glass. The last-mentioned portion of the rays received on a second pane are reflected, while those which were reflected will pass through another pane without reflection. 629. This may demonstrate that the conditions requisite to the permeability of media by rays is affected by diversities of intestinal arrangements which are inscrutable to us. 630. The interval between the lower boundaries of the first spiritual sphere and the second is estimated at thirty miles as a maximum, but this interval is represented to be less, as the spheres between which it may exist are more elevated or remote from the terrestrial centre. 631. Each sphere is divided into six “circles” or plains. More properly these may be described as concentric zones, occupying each about one-sixth of the space comprised within the boundaries of the sphere. There being six subdivisions to each of the six spheres, in all there must be thirty-six gradations. 632. These boundaries are not marked by any visible partition, but spirits have in this respect a peculiar sense, which makes them feel when they are passing the boundaries of one sphere in order to get to the next. 633. This allegation of the existence of an invisible spirit world within the clear azure space intervening between the surface of this globe and the lunar orbit may startle the reader; and yet this idea may have been presented by Scripture to the same mind, without awakening skepticism. It was urged by a spirit friend—Is it more wonderful that you should find our habitations invisible, than that we are invisible?