CLIMATIC CONDITIONS OF THE UNITED STATES. 



375 



C. MOISTURE-TEMPERATURE INDICES (^P/EXT) BASED ON TEMPERATURE 



SUMMATION-INDICES OBTAINED BY THE EXPONENTIAL METHOD (TEM- 

 PERATURE COEFFICIENT OF 2.0), FOR THE PERIOD OF THE AVERAGE 

 FROSTLESS SEASON. (TABLE 22, PLATE 71.) 



The same values for P/E are used here as in the preceding case, but 

 the temperature indices are taken from table 7, column 2. The 

 products are presented in the third column of table 22. They are 

 shown graphically on the chart of plate 71, the discussion of which will 

 be postponed until the next following chart has been presented. 



D. MOISTURE-TEMPERATURE INDICES BASED ON TEMPERATURE SUMMA- 



TION-INDICES OBTAINED BY THE PHYSIOLOGICAL METHOD (LIVINGS- 

 TON'S, 1916) INDICES FROM LEBENBAUER'S 1915 MEASUREMENTS FOR 

 YOUNG MAIZE SHOOTS, FOR THE PERIOD OF THE AVERAGE FROSTLESS 

 SEASON. (TABLE 22, PLATE 72, AND FIG. 18.) 



The values for P/E are the same here as in the two preceding cases, 

 but the temperature indices are taken from table 7, column 4. The 

 products are given in the fourth column of table 22, and the chart 

 therefor is shown as plate 72. The discussion for plates 70, 71, and 72 

 will now be given. 



E. CONCLUSIONS FROM THE STUDY OF THE THREE FORMS OF MOISTURE- 



TEMPERATURE PRODUCTS. (FIG. 18.) 



The direction of zonation on all three of these moisture-temperature 

 charts is at once seen to be essentially the same. A glance at the data 



ijs- 127' 1J5* iM° 121' use 117- Hi* ii3' 111' iw'.io?" iOo° 103° m' ii9f 97° S5° as" 91° }.»• 67° B5' "' si° :o' ::• :5° »° -J" m° <7' Co' 



Fig. 18. — Moisture-temperature zonation, according to moisture-temperature products (physio- 

 logical method) for period of average frostless season. Moisture-temperature provinces: 

 Very high, more than 13 ; high, 7 to 13; medium, 4 to 7; low, 1 to 4; very low, less than 1. Nu- 

 merical values represent thousands. (See also Plate 72.) 



