( 554 ) 



2. Taille IV sliows the results of tiie (reatiiieiit of the frequeiicics 

 given in Tahle I, as imliealed. If the (ieviatioii from the aritli- 

 metical mean is denoted by f, then : 



M 



y n—\ n 



1 ,_ 1 



2 AP 



TABLE IV. 



From this summarj it appears that tlie frequency curve of baro- 

 metric heights, as derived from observations made at Helder, shows 

 systematic departures from the normal curve corresponding to the 

 exponential law. For all months (e.vcejit February and July) h is 

 greater than k' ; in February these factors are equal and the curve 

 is nearly a normal one, in .July h' ^ //. 



In agreement with this result the calculated value of n is always 

 (except in the two months mentioned) less than its true value ; the 

 departures tVom the normal law are greatest in winter, smallest in 

 summer time. 



It may be noticed that the departures from the normal curve, 

 given in table II, are generally of an opposite sign to those which 

 are found in the great majority of series of errors : whereas for 

 the latter the rule holds that small deviations occur oftener than is 

 required by the normal law (in which case A' ^ // and .r calc. ^ .t), 



