L] 



Introduction 



lxxv 



multiply by plus and minus abscissae increasing by units — the 'working unit.' 

 Thus an error made in an early moment may be carried on to the later moments. 

 To control the results Table L was calculated a number of years ago, and from it 

 the fourth moments for such frequencies as most usually occur can be read off at 

 sight, and the raw fourth moment column thus tested before proceeding further. 



(i) 



(ii) 



(iii) 



(iv) 



(v) 



(vi) 



(vii) 



*2 



