8 ozs. to open the fissure to the width of 4 mm.--
that is, the width before the root was extracted. But the part of the
radicle (only .1 of an inch in length) which was embedded in the hole,
probably exerted a greater transverse strain even than 8 lbs. 8 ozs., for
it had split the solid wood for a length of rather more than a quarter of
an inch (exactly .275 inch), and this fissure is shown in Fig. 55. A second
stick was tried in the same manner with almost exactly the same result.
Fig. 56. Wooden pincers, kept closed by a spiral brass spring, with a hole
(.14 inch in diameter and .6 inch in depth) bored through the narrow closed
part, through which a radicle of a bean was allowed to grow. Temp. 50o -
60o F.
We then followed a better plan. Holes were bored near the narrow end of two
wooden clips or pincers (Fig. 56), kept closed by brass spiral springs. Two
radicles in damp sand were allowed to grow through these holes. The
[page 76]
pincers rested on glass-plates to lessen the friction from the sand. The
holes were a little larger (viz..14 inch) and considerably deeper (viz.
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