l68 TIME 



summarizes the results of a great number of measurements made 

 without any preconceived idea, and a curve obtained by expressing 

 quantitatively the consequences of a simple reasoning based on 

 common sense and psychological observation is very striking. 



A year is thus physiologically and psychologically much 

 longer for a child than for its parents. Supposing the parents 

 to be forty years old and the child ten, one year will represent 

 for the child about the same length of time as three (derived 

 from constant A) or four (derived from the hyperbola) years 

 for the parents. If the child is younger the difference will be 

 still more marked, but we have no experimental figures where- 

 from it could be computed. The hyperbola of Fig. 30 might 

 furnish them, but it is probable that a satisfactory accord can 

 be obtained only between the extreme limits of fifteen and 

 sixty years of age. The diagram of Fig. 31 represents the 

 apparent values of one year at different ages with respect to 

 its value at the age of twenty, taken as unit. It can be seen 

 that we limited ourselves to the age of ten. 



There is nothing, moreover, to prove that the hyperbolical 

 rate is valid beyond this age. It is impossible to speak of the 

 notion of time in a very young child and it is extremely 

 probable that the rate of cicatrization is not increased in the 

 proportion indicated by the curve. The extrapolation, repre- 

 sented by the vertical branch which attains an infinite velocity 

 for o years of age, has no meaning. No more meaning than 

 the expression, o years of age, itself; for should one start 

 counting it from the beginning of the time of the fecundation 

 of the egg or from birth? These are purely intellectual bouts. 



The region of maximum curvature, that of our material and 

 conscious existence, is situated exactly midway between 

 infinite velocity and infinite slowness, astride on the hyper- 

 bolic axis which cuts the curve at the point corresponding to 

 thirty-one years and a half. It is impossible not to notice that 

 for a pure relativist it would be very tempting to assimilate 

 every living being to a simple deformation of the four- 

 dimensional space-time continuum so as to explain the non- 

 uniform flow of our time as compared to universal time. 



