. La puissance de mouvement dans les plantes. Les plantes, la botanique. Chap. II. ACTION DE L'KADICLE. 76 Fig. 56. fin. que le bois était très élastiques, le groupe ou la fissure fermé immédiatement après avoir été faite. Après six jours, le stick et de haricots ont été creusées dans le sable humide, et la radicule a été trouvé à être beaucoup plus large au-dessus et au-dessous de l'orifice. La fissure, qui fut d'abord assez fermée, était désormais ouverte à une largeur de 4 mm. ; dès que la radicule a été extrait, il immédiatement fermé à une largeur de 2 mm. Le stick a ensuite suspendu horizontalement par un fil fin en passant par le trou rempli dernièrement par le radic

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. The power of movement in plants. Plants; Botany. Chap. II. ACTION OF THE KADICLE. 76 Fig. 56. end. As the wood was highly elastic, the split or fissure closed immediately after being made. After six days the stick and bean were dug out of the damp sand, and the radicle was found to be much enlarged above and beneath the hole. The fissure, which was at first quite closed, was now open to a width of 4 mm.; as soon as the radicle was extracted, it imme- diately closed to a width of 2 mm. The stick was then suspended horizontally by a fine wire passing through the hole lately filled by the radicle, and a little saucer was sus- pended beneath to receive the weights; and it required 8 lbs. 8 ozs. to open the fissure to the width of 4 mm.—that is, the width before the root was ex- tracted. But the part of the radicle (only •! 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 ex- actly the same result. 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 »and were allowed to grow through these holes. TJie. Wooden pincers, kept closed by a spiral brass spring, witb n hole ("14 inch in diameter and '6 inch in depth) bored through the narrow closed ]iart, through which a radicle of a bean was allowed to grow. Temp. 50°-60° F.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Darwin, Charles, 1809-1882; Darwin, Francis, Sir, 1848-1925. New York, Appleton

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