784 EXPERIMENT STATION RECORD. 



account of the large stumpage of this timber and the present demand for information 

 regarding it. In testing the red gum comparisons were made with hickory, which 

 it is proposed to use asa substitute, but a careful examination of the mechanical prop- 

 erties of the red gum indicates that it is inferior in strength to the poorest grade of 

 hickory. In an appendix the results of the different tests are given- in tabular form. 



SEEDS WEEDS. 



Seed selection according to specific gravity, V. A. Clark (New York Stati Sta. 

 Bui. 256, pp. 367-425, pis. 2, dgms. 4)- — The investigation here reported is an out- 

 growth of work begun by the horticulturist of the station on seed selection as applied 

 to the breeding of grapes, and the present account is presented as a tentative one 

 subject to future verification. 



Two methods were used in studying the specific gravity, one being designated as 

 the method of separates and the other the method of samples. The method of sep- 

 arates is more or less arbitrary, and has been frequently employed to separate lots of 

 seed into 2 or 3 lots of generally equal quantities. The separation by samples is 

 through the use of the pyenometer method, in which the selection is made according 

 to specific gravity. This method gives very exact results, but is slow of application 

 and would not be suited to garden use. 



The writer in his experiments used a series of salt' solutions differing in their spe- 

 cific gravity by 0.01. It was found unnecessary to use solutions differing by less than 

 this, as there was little or no difference in the cultural characters of seeds when sep- 

 arated by no more than 0.01 of their specific gravity. The experiments were carried 

 on with seeds of grapes, mustard, timothy, clover, peas, peppers, turnips, cabbage, egg 

 plant, etc., and the author discusses the range and distribution of seeds with respect 

 to their specific gravity and the possibility of separating foreign matter from seeds by 

 means of solutions, the relation Ijetween specific gravity of seeds and vigor of germina- 

 tion, the relation between specific gravity of seeds and their color and vitality, etc. 



It was found that seeds of the same lot are commonly distributed through a con- 

 siderable range of specific gravity, and that if the seeds are of good quality the 

 larger part of them will fall within a relatively narrow range near but not at the 

 upper limit of specific gravity for the variety. In the case of oil-bearing seeds the 

 range for greatest frequency of distribution is somewhat lower. Specific gravity may 

 in many instances be utilized as a means of separating foreign matter from samples 

 of seed. 



A definite correlation was found to exist between the specific gravity of seeds and 

 their germination. Seeds of low specific gravity do not germinate at all. Those of 

 slightly higher specific gravity germinate poorly and in many cases produce compar- 

 atively weak plants, while those of the highest specific gravity show the highest 

 germination, except in the case of oil-bearing seeds, as already noted above. In 

 some species there was found a correlation between the specific gravity of the seed 

 and its color, and to some extent a similar correlation appears to exist between the 

 specific gravity of the seed and the vigor of the resulting plant. Various factors as 

 influencing differences in the specific gravity are discussed. 



The author gives a bibliography of some of the more important works relating to 

 the subject. 



Seed testing and instructions for sampling, R. S. Seton ( Yorkshire Col., Leeds, 

 and Yorkshire Council Ayr. Education [Pamphlet] 33, 1903, pp. 4). — A statement is 

 given of the conditions under which seed testing is undertaken by the Yorkshire 

 College, and directions for the methods of sampling and size of samples required, 

 together with a schedule of charges made for reporting upon the different varieties 

 of seeds. 



Adulteration of alfalfa seed, J. Wilson (U. S. Dept, Agr., Office of the Secretary 

 Circ. 12, pp. 2). — A brief report is given of investigations of alfalfa seed which were 



