10 



A New Method of Treating 



"deficient," "scanty " and "light." All values falling between 

 two corresponding subsidiary curves are classed as "moderate." 

 In the diagram the regions of " moderate " values have been 

 shaded. Finally two more curves were set off from the lines 

 of averages at such distances from them that one-twelfth of the 

 total number of values fell respectively above the upper and 

 below the lower curves. The chance that a given value 

 should fall outside the limits defined by one or other of these 

 curves is accordingly one in twelve, and thus the values to 

 which the adverb " very " is to be prefixed can be identified. 

 In the diagram these curves are shown dotted. 



In the warm season of the year the warmth of the weeks can 

 be classified entirely on the basis of accumulated temperature 

 above 42 0 , but during the cold months the accumulated tem- 

 perature above 42 0 only serves to identify the weeks of unusual 

 warmth. The weeks of deficient warmth have to be identified 

 from the amount of accumulated temperature below 42 0 . 

 Weeks which fail to reach the limit for " unusual " on the 

 score of accumulated temperature above 42 0 and the limit 

 for " deficient " on the score of accumulated temperature 

 below 42 0 are classified as " moderate." Weeks in which the 

 accumulated temperature " above 42 0 " and " below 42 0 " 

 both surpass the critical values have not occurred in the past 

 25 years. 



A short account of the details of the method of constructing 

 the working diagrams will be of interest. As the method is 

 precisely similar in all cases, we will confine our attention to 

 the consideration of the rainfall in District 4, " Midland 

 Counties," for which the classification diagram is reproduced 

 in the upper diagram A of Fig. 4, on an enlarged scale. In 

 order to take account of the seasonal changes in the range of 

 the divergence from the average, the year was divided into 

 eight periods of six or seven weeks, as follows :— 



6 weeks 



2nd 



to 7th weeks 



7 „ 



8th 



» Hth 



7 



15th 



2lSt 



6 „ 



22nd 



v 2 7th „ 



6 „ 



28th 



» 33rd 



7 „ 



34th 



40th „ 



7 „ 



41st 



„ 47th „ 



6 „ 



48th 



„ 1st „ 



January 8 to February 1 8 

 February 19 to April 8 

 April 9 to May 27 

 May 28 to July 8 

 July 9 to August 19 

 August 20 to October 7 

 October 8 to November 25 

 November 26 to January 8 



