. Agriculture through the laboratory and school garden. Agriculture. 310 AGRICULTURE. of the Petri dish and hold it in position by means of clips made of spring brass wire (Figs. 51, 52). (See Stevens' " Botany," p. 25.) Wind the clock, and set it in its normal position—that is, with the hour-hand spindle. m\ Stevens' "Introduction to ; Copyright, 1902, by D. C. Heatl & Co. KIGS. 51 AND 52.—SEEDLINGS OF INDIAN CORN Grown in sawdust in a Petri dish while revolving by clockwork one revolution per hour. The axis of revolution is horizontal, the plane of the dish ver
. Agriculture through the laboratory and school garden. Agriculture. 310 AGRICULTURE. of the Petri dish and hold it in position by means of clips made of spring brass wire (Figs. 51, 52). (See Stevens' " Botany," p. 25.) Wind the clock, and set it in its normal position—that is, with the hour-hand spindle. m\ Stevens' "Introduction to ; Copyright, 1902, by D. C. Heatl & Co. KIGS. 51 AND 52.—SEEDLINGS OF INDIAN CORN Grown in sawdust in a Petri dish while revolving by clockwork one revolution per hour. The axis of revolution is horizontal, the plane of the dish vertical. Gravity as a direct- ive agent is eliminated, and roots and shoots grow out in the direcftion in which they happen to be pointed. Grown in sawdust in a Petri dish which was kept stationary in a ver- tical position. Gravity is acting as a directive agent, and the roots find and take the downward and the shoots the upward direction, irrespective of the directions toward which they were originally pointing. horizontal. Prepare seeds in another dish in exactly the same manner, but fasten it so that it will stand ver- tically on its edge. In the first experiment the directive effect of gravity would be neutralized by the revolution of the dish, while in the second gravity may exercise its usual influ- ence on the direction taken by root and shoot. Compare results as to direction of radicle and plumule.* * Since the seeds are not covered by the sawdust, their progress in germination may be observed at any time without interrupting the experiment. The position occupied by the parts of the seed- lings can easily be recorded for any period by tracing with ink on the cover immediately over 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 Jackson, Caroline Ruth, 1871- [from old catalog]; Daugherty, Mil
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