THE PERCEPTION OF TIME. 611 



ACCUEACY OF OUR ESTIMATE OF SHORT DURATIONS. 



We must now proceed to an account of iha facts of time- 

 perception in detail as preliminary to our speculative con- 

 clusion. Many of the facts are matters of patient experi- 

 mentation, others of common experience. 



First of all, we note a marked difference between the ele- 

 Tnentary sensations of duration and those of space. The former 

 have a much narrower range ; the time-sense may be called 

 a myopic organ, in comparison with the eye, for example. 

 The eye sees rods, acres, even miles, at a single glance, aud 

 these totals it can afterward subdivide into an almost infi- 

 nite number of distinctly identified parts. The units of 

 duration, on the other hand, which the time-sense is able 

 to take in at a single stroke, are grouj)s of a few seconds, 

 and within these units very few subdivisions — jDerhaps 

 forty at most, as we shall presently see — can be clearly 

 discerned. The durations we have practically most to deal 

 with — minutes, hours, and days — have to be symbolically 

 conceived, and constructed by mental addition, after the 

 fashion of those extents of hundreds of miles and up- 

 ward, which in the field of space are beyond the range of 

 most men's practical interests altogether. To ' realize ' a 

 quarter of a mile we need only look out of the window aud 

 fed its length by an act which, though it may in part result 

 from organized associations, yet seems immediately per- 

 formed. To realize an hour, we must count ' now ! — now ! 

 — now! — now! — ' indefiuitelv. Each 'now' is the feeling 

 of a separate hit of time, aud the exact sum of the bits 

 never makes a very clear impression on our mind. 



How many bits can we clearly apprehend at once? 

 Very few if they are long bits, more if they are extremely 

 short, most if they come to us in compound ^irouj^s, each 

 including smaller bits of its own. 



Hearing is the sense by which the subdivision of dura- 

 tions is most sharply made. Almost all the experimental 

 work on the time-sense has been done by means of strokes 

 of sound. How long a series of sounds, then, can we group 

 in the mind so as not to confound it with a longer or a 

 shorter series ? 



