132 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1935 



successful. The contrast between the working of the fonnulae before 

 and after their date of preparation will be seen in figure 11. 



Happily in Southern Rhodesia, which in 1922 adopted statistical 

 methods similar to those of India with only 24 years of data to work 

 upon, the results have been eminently satisfactory. Out of 11 years 

 since publication was begun, there have been 8 in which a departure 

 of over 3 inches was given by the formula, and in 7 of these the 

 character was correctly indicated (fig. 12). 



At Batavia the efficient Dutch observatory under Braak started in 

 1909 to issue forecasts founded on the simple rule that low pressure 

 from January to June was followed by abundance of rain from July 

 to December. The rule demanded a more complete persistence of 

 pressure than actually prevails, and in 1927 Berlage adopted a 

 formula based on three local conditions, together with data of the 

 rare rains of northern Peru : this gives, on paper, a relationship of 

 over 0.8. 



In Australia calamitous failures in the rains have long demanded 

 forecasts, and these led to the production of weather cycles, which 

 broke down so frequently that their use was discarded. In spite of 

 this experience, however. Hunt, the Commomvealth Meteorologist, 

 put forward in 1929 a theory of a 4-year period, based on the cool- 

 ing effect of the wide-spread growth of luxuriant vegetation pro- 

 duced by the rainfall in areas that were parched. I believe that the 

 theory has not been adopted officially. 



When we turn from the tropical and subtropical to the temperate 

 regions, where the persistence of conditions is in general conspicu- 

 ously smaller, we must expect greater difficulties in making long- 

 range forecasts. In America the relations of weather and crops 

 have probably been worked out more scientifically than in any other 

 country, so that the commercial value of reliable predicting has long 

 been recognized; and not only by farmers, but by those interested 

 in water supply, in power schemes, in transport, and in commerce 

 generally. Thus one of the Californian hydroelectric companies 

 makes its own forecasts, because it may spend $4,000,000 more for 

 crude oil in a dry than in a wet year. In a country of exuberant 

 vitality it is not surprising that many efforts should have been made 

 to provide for the general demand. In an article in 1927, by C. F. 

 Brooks, we read that in the absence of forecasts " western farmers 

 have paid a ' raimnaker ' thousands of dollars at a time " actually 

 to produce rain ; that during the previous 10 years " well over 50 

 long-rangers of greater or lesser repute have been publishing and, 

 in a great many cases, accepting money for worthless or damaging 

 forecasts." As in Europe, they have predictions based on occur- 

 rences on critical days, such as Candlemas or St. Swithin's, as well 



