The wood was so cut that the
short space of radicle between the mouth of the hole and the bean could not
bend laterally on three sides; but it was impossible to protect the fourth
side, close to the bean. Consequently, as long as the radicle continued to
increase in length and remained straight, the weighted bean would be lifted
up after the tip had reached the bottom of the shallow hole. Beans thus
arranged, surrounded by damp sand, lifted up a quarter of a pound in 24 h.
after the tip of the radicle had entered the hole. With a greater weight
the radicles themselves always became bent on the one unguarded side; but
this probably would not have occurred if they had been closely surrounded
on all sides by compact earth. There was, however, a possible, but not
probable, source of error in these trials, for it was not ascertained
whether the beans themselves go on swelling for several days after they
have germinated, and after having been treated in the manner in which ours
had been; namely, being first left for 24 h. in water, then allowed to
germinate in very damp air, afterwards placed over the hole and almost
surrounded by damp sand in a closed box.
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