On the Logarithmic Frequency Distribution and the Semi-Logarithmic Correlation Surface

I NTRODUCTION* * 'T'he metho(d of treatinig frequency curves as developed chiefly l)y Fdgeworth, Kapteyn. Vanl U veni and( NVicksell occupies an iml)ortant place in both tlheoretical anid applied statistics. The essenice of this metlhod maxv he briefly sunmimarized as follows: Suppose a fulnctioni of the variable z is distributed according to the normal law of error. 'rlTen. z certainily canniiot be also normallv (listributed, ivunkss the funiction is a liniear functioni of z . Withlout losinig genierality. we shall write the niormiially distributed functioni in stanidard units as = f6z). Thus the origin of z is its mean ani(l the unit of x is its stand(lar( (leviation. Trhe relative frequency of values of x betw-een x andt x + dx is, therefore