SEEDS- — WEEDS. 1047 



On the salt-water method of the selection of seeds, T. Yokoi 

 [Imp. Univ. Col. Agr. [Tokyo] Bui., Vol. 3, No. 5, pp. 421-439). — The 

 method of selecting seed by specific gravity is said to have been prac- 

 ticed in China and Japan for more than 250 years. The author shows 

 by a number of experiments that there is no constant relationship 

 between the specific gravity and absolute weight of seed, owing to a 

 number of factors, such as the varying quantity of fat, ethereal oils, 

 water, free air, etc. It is also shown that the specific gravity is not 

 an index of the actual amount of nutriment for the nourishment of a 

 plautlet from a seed. A series of experiments with barley is quoted 

 in which seed of the same specific gravity, but of different weights, 

 and those having the same weight but different specific gravity, were 

 compared. It appeared that seed having the greatest absolute weight 

 produced larger plants than those of the highest specific gravity, show- 

 ing that the absolute weight of tbe seed has an intimate relation to 

 productive power, but the productive power has little or no relation to 

 specific weight. 



A method of selection by the use of salt solutions is described, in 

 which different strengths of solution are employed for different kinds 

 of seed. The results obtained by this method, though not scientific- 

 ally accurate, are said to be much more satisfactory than the ordinary 

 specific gravity tests, and the method is quite widely employed in 

 Japan. 



On the selection of rape seed, C. Kobayashi {Imp. Univ. Col. 

 Agr. [ Tokyo] Bui., Vol. 3, No. 5, pp. 440-468). — Investigations were con- 

 ducted to ascertain the relation between the absolute weight and 

 specific gravity of rape seed, the relation between the absolute weight 

 and specific gravity of the seed and their germination, and the relation 

 between the specific gravity of rape seed and their oil content. Briefly 

 summarized the conclusions are that seeds of medium specific gravity 

 have a more regular shape, are large, plump, heavy, and consist mainly 

 of the heavier seeds when compared with those having either maximum 

 or minimum specific gravity. The relation of the specific gravity and 

 absolute weight of rape seed to germination shows that seeds of medium 

 specific gravity are always superior in their germinating capacity, and 

 produce more vigorous seedlings than those having a much higher or 

 lower specific gravity. Heavy seeds produce larger seedlings than 

 lighter ones, and if the seed of a given variety of rape be divided into 

 groups according to specific gravity and absolute weight, on the whole, 

 that of medium specific gravity is best for sowing. In estimating the 

 oil content of rape seeds, those having medium specilic gravity were 

 found richest in oil. 



On the effect of soaking rice seeds, T. Yokoi {Imp. Univ. Col. 

 Agr. [Tokyo] Bui., Vol. 3, X<>. 5, pp. 469-473). — Attention is called to the 

 loss in the dry weight of, seeds, caused by soaking them in wider for 

 varying periods of time. A number of experiments are quoted in 

 which it is shown that soaking seel for 21 hours entailed losses of from 



