1907.] 



met with in it. The " district values " for the various meteoro- 

 logical elements considered are the arithmetic means of the 

 values for stations in the district. 



It may be objected that the mean value determined in this 

 way does not represent the actual occurrence at any one point 

 in a district, but experience has shown that the divergence of the 

 various elements from their averages at the individual stations 

 are, broadly speaking, of the same character as the concurrent 

 divergence of the district value from its average, and, as a 

 general rule, it is with the divergence from the average that we 

 have to deal in examining statistically the effect of meteoro- 

 logical conditions on phenomena influenced by the weather. 

 The values for individual stations are given on a separate 

 page of the Weekly Weather Report. 



A further advantage possessed by the method of working 

 with values for districts is that it is possible to maintain the 

 continuity of the records even if observations are discontinued at 

 individual stations. The effect of the records from a single 

 station on the mean for the district is small, and, by exercising 

 judgment in the selection of the stations, it is possible that the 

 whole series of stations in a district may become changed in 

 course of time without materially altering the mean for the 

 district. 



It is a matter for great regret that the meteorological districts 

 are not the same as the divisions of the country adopted by the 

 Board of Agriculture. The consequence is that a direct com- 

 parison between the meteorological and agricultural statistics 

 is not possible. A readjustment of the district boundaries is, 

 however, not immediately practicable, as it would necessitate 

 the recalculation of the averages for districts, and this would 

 involve much labour. In the Weekly Weather Report the 

 station values have been arranged, since the commencement of 

 1906, in a manner which allows of the calculation of values 

 for sub-districts which can be combined to agree approximately 

 with the divisions of the Board of Agriculture. 



Accumulated Temperature. — ( Questions of warmth arc dealt 

 with in the Weekly Weather Report mainly on the basis of 

 " accumulated temperature," and before discussing the recent 

 additions to the report it will be desirable to give some ex- 

 planationot this term. Accumulated temperature takes account 



