Mar.i,i 9 2i Temperature Efficiency for Ripening of Sweetcorn 803 



Table IV. — Comparison of the rates of sweetcorn ripening in different localities, based 

 upon the exponential indices corresponding to the normal mean temperatures of the 

 ripening seasons 



Locality. 



Ripening season. 



Time be- 

 tween pre- 



nnlk and 

 best edible 

 milk stage. 



Length of 



time in 



best edible 



stage. 



Charleston, S. C... 

 Baltimore, Md. . . . 



New Haven, Conn 

 Portland, Me 



June 17 to 31. 

 July 1 to 15.., 



Aug. 1 to 15.. 

 Aug. 16 to 31. 

 Sept. 1 to 15.. 

 Sept. 16 to 30 

 Oct. 1 to 15... 



Aug. 1 to 15. . 

 Aug. 16 to 31. 



Sept. 1 to 15. 

 Sept. 16 to 30 



Days. 

 7.0 



6-5 



8.0 



8-5 



9-5 



"•5 



14. o 



9-5 



10. s 



14. o 

 16. o 



Days. 



2 -5 

 3-o 



3-o 

 4.0 



5-o 



3-° 



3-5 



4-5 

 5-5 



The results given in Table IV are simply the average expectations, 

 calculated for a 20- year period. If the mean temperature for a particular 

 season deviates to any considerable extent from the normal mean, the 

 rate of ripening for this season will be greater or less, depending upon the 

 direction of the deviation, than that calculated from the normal mean 

 temperature. In order to test the possible magnitude of deviation from 

 the average expectation, the ripening rates were calculated for the highest 

 and lowest mean August temperature at Baltimore from 1871-1918. 

 These results together with those calculated from the normal mean 

 August temperature for the same period are given in Table V. Data 

 were not available from which to derive the exponential indices cor- 

 responding to the daily mean temperatures for the month as was done 

 in calculating the data from normal mean temperatures given in Table 

 III. However, the results suffice to indicate that for the most extreme 

 seasons the number of days required for the two periods of ripening 

 under consideration -would not vary more than a day or two in either 

 direction from the calculated average. If the particular season in 

 question is unusually hot, one day would have to be subtracted from the 

 average prediction. If, on the other hand, the season is unusually cool, 

 one day would have to be added to the average expectation. This 

 applies particularly to Maryland conditions. 



In making the foregoing predictions it was assumed that most of the 

 ears of a given crop will ripen at practically the same rate. This was 

 found to be true in the experimental crops grown from home-selected 

 seed. For canning purposes it is essential to use seed that will insure 

 the maximum uniformity in ripening. 



