35 



The period of time prior to the date of normal maximum emer- 

 gence during which the accumuhited temperature must be ascertained 

 in order to determine the total amount of accunudated temperature 



NORM/^L MCy^N MO/vr/-fLy reM/^'^R^rufi'E curve 

 /3o^ A^EA/^ /wo/vTHL y rrA^P£Ryf ri/R£r Curve 



Fig. 1.— Diagram showing normal mean monthly temperature and the mean monthly tempera- 

 ture during 1904 at Victoria, Tex. (original). 



necessary for maximum emergence, and the average temperature of 

 the date on which this accumulation must begin both for the normal 

 and any individual 3^ear, must be determined and will doubtless 



estimated, for in the spring the latter half of the month will be warmer and 

 in thf fall cooler than the first half. An examination of the daily temperature 

 ■curves for any year corroborates this view. 



Considering that the wee\ils first commence to emerge normally at (38° F., 

 and that the maxiaaum emergence is normally at 78° F., then the amount of 

 temperature necessary to accumulate after tlie first emergence before the 

 maximum emergence will be represented by the area ABC, and the maxinuim 

 emergence will be at the point B. where the normal mean temperature line 

 crosses 78° F., or, approximately. May 15. In 1904 the first emergence would 

 theoretically have taken place at A', where the mean temperature crosses 08° F., 

 or about March 12. After tliat for about a month there was an excess of 

 temperature and then a deficiency until July. The mean temperature line 

 did not cross 78° F. until about June 3. 



But if we ascertain the date of maximum emergence in 1904 by the hypoth- 

 esis proposed we would proceed as follows : The point of departure of the 



