THE FOURTH DIMENSION 121 



and when we attempt to form any mental conception of it 

 and its inhabitants, we are compelled to adopt, to a certain 

 extent, the idea of the third dimension. 



But at the same time we must remember that since the 

 ordinary mechanic and the school-boy who has studied ge- 

 ometry, find no difficulty in conceiving of points without 

 magnitude, lines without breadth, and surfaces without 

 thickness conceptions which seem to have been impos- 

 sible to Buckle, a man of acknowledged ability it may be 

 possible that minds constituted slightly differently from 

 that of myself and some others, might, perhaps, be able to 

 form a conception of a fourth dimension. 



Leaving out of consideration the speculations of those 

 who have woven this idea into romances and clay-dreams we 

 find that the hypothesis of a fourth dimension has been 

 presented by two very different classes of thinkers, and 

 the discussion has been carried on from two very different 

 standpoints. 



The first suggestion of this hypothesis seems to have 

 come from Kant and Gauss and to have had a purely meta- 

 physical origin, for, although attempts have been made to 

 trace the idea back to the famous phantoms of Plato, it is 

 evident that the ideas then advanced had nothing in com- 

 mon with the modern theory of the existence of a fourth 

 dimension. The first hint seems to have been a purely 

 mathematical one and did not attract any very general at- 

 tention. It was, however, seized upon by a certain branch 

 of the transcendentalists, closely allied to the spiritualists, 

 and was exploited by them as a possible explanation of 

 some curious and mysterious phenomena and feats exhibited 

 by certain Indian and European devotees. This may have 

 been done merely for the purpose of mystifying and con- 



