ON THE 



SELECTION 



OF RAPE SEED. 



445 



It was stated by Marek that seeds of greatest absolute weight 

 are the best in quality and yield the largest crops ; but the absolute 

 weight of any seed has no constant relation to its specific gravity. 

 Hellriegel, Lehmann, Wollny, Marek and others have found that 

 although the Aveight of a seed varies under various conditions, the 

 heaviest and largest seeds produce the largest and best crops and 

 are best for sowing. As regards the specific gravity, opinions are 

 divided, Hellriegel, Wollny and Marek being of the opinion that 

 the specific gravity of a seed and its quality do not always go 

 together. The results obtained by many workers of our College 

 show, however, that in cereals especially those which have hulls, 

 such as rice, barley except the naked sort, etc., the specific gravity 

 and absolute weight and consequently the quality have a certain 

 clo.se relation with each other. 



I have furthermore examined the average specific gravity of 

 rape seed, classed in three groups of different weight. 200-250 

 grains were taken from each group and the specific gravity deter- 

 mined by means of the pycnometer : — 



TABLE H. 





W'eiglit of one 

 grain. 



Sp. gr. of the 

 sort Chosen. 



.Sp. gr. of the 

 sort Okinia. 



Sp. gr. of the 

 sort Hamburg. 





4.5 cS: nuire iiig. 



1. 105 



1-093 



1. 136 





3.0-4.0 



1. 121 



1.098 



1. 151 



Lightest 



3,0 aivl less. 



1. 135 



1. 105 



1. 1 60 



In the above, the seeds are but roughly classified ; e. g. in the 

 heaviest group there are of course, included several grains, whose 

 specific gravity are less than L08 or even 0.025, while lightest group 

 include also those of 1.145 and more. It would therefore, be 

 erroneous to conclude from the above table that the seeds which 

 have a smaller specific gravity have the greatest absolute weight. 

 On the contrary the above results agree quite well with those of 

 Table A, and we may state that the results always agree quite well 

 whether the absolute weight was measured for seeds of different 

 specific gravities or whether the specific gravity was determined for 

 seeds of different absolute weights. In either case the seeds which 

 had a medium specific gravity had the greatest absolute weight. 



