462 



KOBAYASHI. 



These results show that the germination energy and percentage 

 are about the same in the seeds of different specific gravities and 

 absokite weights, but that, for a given specific gravity, tlie length 

 of the shoots and roots and the dry matter of their seedlings 

 increase proportionately with the weight of the seeds, and that when 

 we compare seeds of the same absolute weight but of different 

 specific gravities the results are found to be in favour of the seeds of 

 medium specific gravity on the average. In the preceding chapter 

 it has been proved that the seeds of medium specific gravity have 

 also, on the average, greater absolute weight than those of 

 maximum and minimum specific gravities and consist mainly of 

 heavy grains. Thus it may be stated that as large heavy seeds 

 produce good seedlings and best crops, seeds of medium specific 

 gravity should be selected in the case of rape. For the selection of 

 rape seed, however, its oil content must primarily be taken into 

 account and it is very important to ascertain whether the seeds 

 which have strong germination power and which consequently 

 promise a better growth and superior crops always contain more oil 

 than the weaker or not. The results of my experiments on this 

 point will be described in the next chapter. 



III. The Relation between the Specific Gravity of Rape 



Seed and its Oil Content. 



The object of this experiment was to find out the specific 

 gravity which should be taken as the criterion for the so-called 

 " specific gravity selection," by means of which rape seeds richest 

 in oil could be separated and to determine which sorts of rape are 

 comparatively rich in oil. Thus the experiments were divided into 

 two groups : — 



a. ) Those directed to determine the relative richness of 

 different sorts in oil. 



b. ) Those pertaining to the relation of the oil content to 

 the specific gravity of seed. 



Soxlet's method of fat estimation was followed in this 

 investigation. 



a.) Relative Richness of different Sorts in Oil. 



Four sorts of rape seed were taken and their specific gravities 

 were determined, and the percentage of water and oil was then 

 measured ; thus >- 



