(Drapers Company Research Publica- tions), and of the Correction formulae by William Brown in the reports of the VInie Congres Internationale de Ptychologie, Geneve, 1909 ( Some Experimental Results in Correlation ).

In this article I have nowhere discussed at length the advantages and limitations of Dr Spearmans formulae : instead of burdening a lengthy paper with further mathematical technicalities, I have preferred to leave the merits and defects of the methods I have endeavoured to test and illustrate to be inferred from the results they yield by those more competent to form an opinion on mathematical questions than myself.

I may, however, add that most of the figures essential to my general psycho- logical conclusions have been checked by the more elaborate and better accredited formulae, and the discrepancies have been found to be practically negligible.

Crepancies, 2

When there is complete inverse proportionality the coefficient should be 1.