THE FOURTH DIMENSION. 



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tances. The plain, that is, the two-dimensioned space, is accord- 

 ingly viewed by him from points outside of the plain as "open" in 

 all directions. Exactly so, in ZOllner's theory, must three-dimen- 

 sioned spaces appear, when viewed from points in four-dimensioned 

 space, namely, as "open"; and the more so in proportion as the 

 point in question is situated at a greater distance from the place of 

 our body, or in proportion as the soul ascends to a greater height in 

 this fourth dimension. Zollner thus explains clairvoyance as a con- 

 dition in which the soul has displaced itself out of its three-dimen- 

 sioned space and reached a point which with respect to this space 

 is four-dimensionally situated and whence it is able to contemplate 

 the three-.dimensional world without the interference of intervening 

 obstacles. 



The following remark is to be made to this explanation. The 

 reason why we have a better and more extended view from a bal- 

 loon than from places on the earth is simply this, that between the 

 suspended balloon and the objects seen at a distance nothing inter- 

 venes but the air, and air allows the transmission of light, whereas, 

 at the places below on the earth there are all kinds of material 

 things about the observer which prevent the transmission of light 

 and either render difficult or absolutely impossible the sight of 

 things which lie far away. In the same way, also, from a point in 

 four-dimensioned space, a three-dimensional object will be visible 

 only provided there are no obstacles intervening. If, therefore, this 

 awareness of a distant object is a real, actual vision by means of a 

 luminous ray which strikes the eye, there is contained in the ex- 

 planation of Zollner the tacit assumption that the medium with 

 which the four-dimensional world is filled is also pervious to light 

 exactly as the atmosphere is. 



The theory that there are four-dimensional spirits who produce 

 the phenomena cited by the spiritualists received special support 

 from the experiments which the prestidigitateur Slade, who claimed 

 he was a spiritualistic medium, performed before Zollner. Of these 

 experiments we will speak of the two most important, the experi- 

 ment with the glass sphere and the experiment with the knots. To 

 explain the connection of the glass sphere experiment with the fourth 



