1894.] Table of Koro'si by tke Method of Contours or Isogens. 21 

 Table II. Values of the Isogens at the Dots. 



ages of the parents to which each point in the straight portion of the 

 same isogen refers are constant. The difference between their ages is 

 of no account whatever in eight or nine tenths of the total number of 

 marriages ; it is only when the wife is older than the husband or when 

 she approaches the limit of the child-bearing age, that this curious 



