CLIMATIC CONDITIONS OF THE UNITED STATES. 



373 



6, column 5), by the corresponding Transeau ratio (table 11, column 

 8). For simplicity, we may represent the first of these factors by the 

 letter T and retain the expression already used (P/E) for the second, 

 whence we may term the resultant index P/E XT. The results 

 obtained are set forth in the second column of table 22. 



The chart for this series of values is shown as plate 70. Its discus- 

 sion may best be combined with those of the two following charts. 



Table 22. — Moisture-temperature indices (P/ExT) jor the -period of the average frostiest 

 season, by remainder (above 39° F.), exponential, and physiological methods. 



The moisture ratios {P/E) from table 12, and the summation indices (T) from tables 9 and 10. 



^ Where a second station is named in parentheses, the evaporation value is for this station. 

 * The values in this column have appeared in Livingston's paper (1916, 2). 



