W. E. BllENCIITiEY AND A. D. HaLL 



199 



* Up to Aug. 12th, the date of cutting. 



Specific Gravity. In 1907 the specific gravity was determined imme- 

 diately the grain had been extracted, by means of a form of vokime- 

 nometer. The curves obtained in 1907 are set out in Fig. 1: they show 



Plot 3 

 R.F. 

 Plot 10 



3 6 9 12 15 18 21 24 27 30 33 36 39 days 



Fig. 1. Curves showing tlie specific gravity of the wheat grain at successive 



periods in 1907. 



that though the experimental error is comparatively large there is 

 evidently a slight falling off in specific gravity for the first four or five 

 periods of three days, after which there is a continual rise up to and 

 after the date of cutting. By combining these results with the deter- 

 minations of water in the grain at each date it is possible to calculate 

 the specific gravity of the dry matter contained in the grain, the mean 

 curve of which for all three varieties is given in Fig. 2. From this it is 

 evident that the specific gravity of the dry matter falls for about twelve 

 days from the beginning of the trials, i.e. until the 22nd day from 

 flowering has been reached, after which it remains constant. 



