168 



Hydration and Growth. 



19° to 20° C, and high relative humidity during the rainfall of Sep- 

 tember 11 and 12. 



The fact that the greatest increase in growth occurs in fruits at 

 diameters between 16 and 25 mm. in diameter, before half the final 

 size is reached, is a point to which we shall recur in the discussion of 

 growth in terms of volume. Thus, in No. 3 the increases in thickness 

 weekly were as follows: 6 mm., 6.3 mm., 2.5 mm., 3.5 mm. (fig. 50). 



12 p.m. m. 12 p.m. m. 



FiQ. 50. — Variations in radial or transverse diameter of a tomato during development in 28 days. 

 Increase is denoted by downward course of the auxographic tracing, and the direct effects of 

 temperatures and relative humidity are illustrated by the record and the accompanying 

 notations in the figure. Amplified 5 times on scale ruled to 5 mm. intervals. 



