Germmation. 23 



we sliall find that the tirst lot will swell fastest, the second 

 next and the third slowest. Pew seeds will absorb enough 

 water from damp air at ordinai-y temperatures to swell 

 much. 



b — TJir' points of confaci. If we weigh, two lots of 

 100 beans each, on a delicate balance, and mix each lot 

 with well-crnmblcd, moist loam in a fruit jar, i)acliing 

 the loam tiglitly in <ine of the jars and leaving it as 

 loose as possible in the other, close both jars to i^revcnt 

 evaporation, and after twenty-four hours sift the beans 

 out of the loam and weigh the two lots again — we shall 

 find that the beans in the jar containing the compacted 

 loam have increased moi'e in weight than the others. 

 This indicates that the beans in this jar have absorbed 

 water fastei' than those in the other, because they were 

 in contact with the moist loam at more points. 



c — Temperature. If we fill t^vo bottles with beans, 

 adding ice water to one, placing it in a refrigerator, and 

 lukewarm water to the other, setting it in a warm room, 

 we shall find that the beans in the hitter bottle will swell 

 more rai)idly than those in the former. This shows that 

 a warm teinperature favors the al)sorption of water — a 

 fact that is true of all seeds. The same would have been 

 true had we planted the beans in two samples of moist 

 eartli, placing these in different temj)eratures. 



d — The nature of the seed-case.* In the bean, Indian 



* The term sei'd-case is here nsed to designate the outer covering of the 

 seed ;is the word seed is understood by the seedsman or plantrr. Every 

 seed, as we buy it in the marljet, or ^vlicn ready for planting, has one or 

 more covering layers. In the peanut, for example, what we here call the 

 seed-case is commonly called the shuck; iu the cocoiinut it is <-alled the 

 shoil; in the bean and Indian corn it is more often called the skin. In 

 botany, the outer coverings of seeds are given different names, as peri- 



