386 



The curves in Fig. liA were, therefore, smoothed as shown, in order 

 to counteract the heterogeneity of the data and to compensate for the 

 probable errors of experimentation and interpretation. This smoothing 

 is not to be construed as a merely mechanical process, but as a kind of 

 averaging of results with a view to the best possible expression of the 

 real effects of temperature and humidity upon the rate of development. 

 The more regular lines in Fig. 14 are thus more truly representative of 

 equal-velocity values than the crooked lines. The best proof that smooth- 

 ing is justified, lies in the fact that the use of the chart made from these 

 curves gives consistent results. 



The harmonized velocity values obtained by the method shown in 

 Fig. 14A were then used in the plotting of the straight-line portions of the 

 solid-line curves in Fig. 13, which are presumably more nearly correct 

 than the corresponding portions of the broken-line curves originally 

 plotted. (The dotted vertical lines through points of equal velocity vahies 

 in Fig. 13 may be compared with the solid lines in Fig. 14 A.) The alpha 

 values of these new curves were checked by the' Von Oettingen method 



Fig. 14A. Method of smoothing velocity curves of Pig. 13. Velocities from 

 Pig. 13 are indicated by dots. The broken lines were drawn connecting these 

 dots, and the solid lines were then drawn by smoothing these lines to bring 

 them into harmony. 



and found to be more satisfactory than those of the old curves. The use 

 of 52.2° F. as the alpha value for the 95 per cent data gave a nearly con- 

 stant time-temperature product over a wider range of temperatures than 

 when 54.8° F. was used. This widening of the straight-line limits is in 

 better accord with the data for other humidities ; also, the time-tempera- 

 ture product is larger and, accordingly, nearer the presumably correct 

 value for the constant. For the 85 per cent humidity data, 51.8° F. 

 similarly proved to be the best alpha value. The data at approximately 

 83° F. were from air-movement experiments in which the rate of air-flow 

 was not that used as standard in the other experiments ; these data were 

 plotted in the absence of other data. The solid line curve, however, is 

 practically an interpolated curve for the plotted points, and it has the 

 same alpha value (51.8° F.) as the broken-Hne curve. In the case of the 



