NO. lO SOLAR RADIATION AND WEATHER STUDIES ABBOT ']'] 



ture or from normal rainfall as just described must show numerous 

 features during any 23-year cycle which would tend more or less 

 strongly to be reproduced in each succeeding 23-year cycle. To test 

 this probability, the data on departures from normals of temperature 

 and precipitation for all available stations were plotted on sheets of 

 specially prepared plotting paper. These sheets were ruled in abscis- 

 sae to represent 276 months or 23 complete years, and in ordinates to 

 present 300 millimeters, or 30 centimeters. 



As an illustration, figures 33 and 34 present the percentage precipita- 

 tion of Peoria, III, and the temperature departures of New York 

 City. Features thought to be common in successive 23-year periods 

 are indicated on the curves by letters. Principal trends are also to 

 be observed. A dotted continuation of the last line of the plot covers 

 the years 1934, 1935, and 1936. This continuation represents the 

 mean expectation as based on former cycles. As the features in 

 former cycles show considerable differences, such a mean can only 

 roughly indicate their future forms. The method of drawing the mean 

 which is the most probable expectancy may be clearly understood by 

 observing the faint construction lines above and below the dotted con- 

 tinuation. Similar continuations for 1934, 1935, and 1936 were drawn 

 before the events occurred, and may be regarded as forecasts for both 

 precipitation and temperature for over 30 stations in the United States. 



A year having elapsed, the actual departures of temperature and 

 precipitation for all of these stations just mentioned were computed 

 and smoothed by 5-month traveling means. These observed results 

 for 1934 were plotted alongside of the predicted values for 1934- By 

 inspection the agreement was then classified as " Excellent," " Fair," 

 " Half and half," or " Bad." Under this classification the cities were 

 grouped as follows : 



A. Temperature. 



Excellent, 7 : Eastport, Key West, Detroit, Salt Lake, Helena, Port- 

 land, San Diego. 



Fair, 17: Albany, New York, Washington, Hatteras, Mobile, Nash- 

 ville, Cincinnati, Chicago, St. Paul, St. Louis, Omaha, 

 Bismarck, Cheyenne, Denver, Santa Fe, Red Bluff, 

 Spokane. 



Half and half, 3 : New Haven, Galveston, North Platte. 



Bad, 4: Charleston, Little Rock, Abilene, San Francisco. 



B. Precipitation. 



Excellent, 1 1 : Eastport, Burlington, New York, Detroit, Chicago, 

 Duluth, St. Paul, St. Louis, Little Rock, North 

 Platte, Bismarck. 



