272 THE WEIGHT TAEIES. 



Column 7 shows the average percentage of loss in 

 the weight of the grass, in making into ha^, when cut 

 in the time of flowering. 



The weight of seeds varies, of course, somewhat 

 from that stated in the above table, according to their 

 quality. Those given in the table are the average 

 weights of good, merchantable seed. In some states, 

 as in Wisconsin, for instance, the legal weight of Tim- 

 othy-seed is forty-six pounds to the bushel ; in others, 

 it is forty-four. The weight of a bushel will depend in 

 part, of course, upon the thoroughness with which it is 

 cleaned. The seeds of the different varieties of rye 

 grass differ in weight, varying from twenty to thirty 

 pounds per bushel ; but the average is from twenty to 

 twenty-five pounds. 



The number of seeds of each species in a pound may 

 be found, of course, by multiplying the numbers in col- 

 umn 3 by sixteen, the number of ounces in a pound. 

 It is obvious, however, that these numbers must vary, 

 like the number of pounds in a bushel ; for it is evident 

 that the lighter the seed, the greater will be the number 

 of seeds in a pound. The numbers stated are the 

 average obtained by careful and repeated trials, and 

 they may be relied on as the average of well-cleaned 

 seed. 



The results stated in columns 4, 5, and 6, were 

 obtained by careful experiment, and will be found to be 

 very suggestive. 



The fact that the soil Used in the experiments to 

 ascertain the proper depth of covering was kept moist 

 during the process of germination, though freely ex- 

 posed to the light, accounts for the large number of 

 seeds germinated without any covering whatever. In 

 ordinary field culture some slight covering is desirable ; 

 but the figures in column 6 show the important fact 



