22 Principles of Plant Culture. 
that the first lot will swell fastest, the second next and the 
third slowest. Few seeds will absorb enough water from 
damp air at ordinary temperatures to swell much. 
(b) — The points of contact. If we weigh, on a delicate 
balance, two lots of 100 beans each, and mix each lot with 
well-crumbled, moist loam, in a fruit jar, packing the loam 
down tightly in one of the jars and leaving it loose as possi- 
ble in the other, close both jars to prevent 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 in weight 
more than the others. This indicates that the beans in this 
jar have absorbed water faster than those in the other, be- 
cause they were in contact with the moist loam at more 
points. 
(c) — Temperature. If we fill two bottles with beans, add- 
ing ice water to one, placing it in a refrigerator, and luke- 
warm water to the other, setting it in a warm room, we shall 
find that tae beans in the latter bottle will swell more rap- 
idly than those in the former. This shows that a warm 
temperature favors the absorption 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 earth, placing 
‘these in different temperatures. 
(d) — The nature of the seed-case.* In the bean, Indian 
* The term seed-case is here used to designate the outer covering of the seed 
as the word seed is understood by the seedman or planter. Every seed, as we buy 
it in the market, or when ready for planting, bas one or more covering layers. In 
the peanut, for exaraple, what we here call the seed-case is commonly called the 
sbuck; in the cocoanut it is called the shell; 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 pericarp, testa, etc., according to their exact office in the make-up of the 
plant. To avoid explaining the technicalties of acomplex subject, it seems prefer- 
able to adopt a term that will include the various words used in botany to designate 
the outer coverings of seeds. 
