136 PSYCHOLOGY. 



on this view, becomes an element in each sensation just as 

 intensity is. The latter every one will admit to be a dis- 

 tinguishable though not separable ingredient of the sensible 

 quality. In like manner extensity, being an entirely pecul- 

 iar kind of feeling indescribable except in terms of itself, 

 and inseparable in actual experience from some sensational 

 quality which it must accompany, can itself receive no 

 other name than that of sensational element. 



It must now be noted that the vastness hitherto spoken of 

 is as great in one direction as in another. Its dimensions are 

 so vague that in it there -is no question as yet of surface 

 as opposed to depth ; * volume ' being the best short name 

 for the sensation in question. Sensations of different orders 

 are roughly comparable, inter se, ivith respect to their volumes. 

 This shows that the spatial quality in each is identical 

 wherever found, for diflferent qualitative elements, e.g. 

 warmth and odor, are incommensurate. Persons born 

 blind are reported surprised at the largeness with which 

 objects appear to them when their sight is restored. Franz 

 says of his patient cured of cataract : " He saw everything 

 much larger than he had supposed from the idea obtained 

 by his sense of touch. Moving, and especially living, 

 objects appeared very large." * Loud sounds have a cer- 

 tain enormousness of feeling. It is impossible to conceive 

 of the explosion of a cannon as filling a small space. In 

 general, sounds seem to occupy all the room between us 

 and their source ; and in the case of certain ones, the 

 cricket's song, the whistling of the wind, the roaring of the 

 surf, or a distant railway train, to have no definite start- 

 ing point. 



In the sphere of vision we have facts of the same order. 

 'Glowing' bodies, as Hering says, give us a perception 

 "which seems roomy [raumhaft) in comparison with that 

 of strictly surface color. A glowing iron looks luminous 

 through and through, and so does a flame." f A luminous 

 fog, a band of sunshine, affect us in the same way. As 

 Hering urges : 



* Philosophical Transactions (1841). 



t Hermann's Haudb. d. Physiol., Bd. m. 1, S 575. 



