Page:Popular Science Monthly Volume 52.djvu/198

184 in the course of a minute or two, so that we should have, as it were, a greatly magnified representation of the movements involved in plant growth. If, for example, our pictures were taken at half-hourly intervals, and shown at a speed of fifty per second, the apparent rate of growth of the plant would be increased no less than ninety thousand times. A slower rate would evidently correspond to a diminished time interval between successive negatives; and this interval should in all cases be so chosen as to insure gradual (though distinctly perceptible) changes in the resulting pictures.

Such views could not fail to produce an effect at once marvelous, unique, and instructive. As pictured upon the canvas, the plants would grow and develop before the eyes of onlookers, throwing out leaf upon leaf, and visibly increasing their dimensions. Here and there a flower or flower cluster might make its appearance, the individual blossoms bursting forth suddenly and remaining visible for a brief period only. The process is clearly applicable to greenhouse or indoor plants of every description, from stately palms or tree ferns down to the most delicate mosses or lichens. Thus, the general phenomena of plant growth may be illustrated with a vividness never before realized. As object lessons in botany, such motion pictures would be invaluable, while the general public, not less than the advanced student of science, would regard them with feelings of the keenest interest.

Instead of photographing an entire plant, we might direct our efforts to the representation of its more interesting details. Thus, an expanding leaf bud or a flower stalk would furnish highly attractive views for the cinematograph. The microscope, too, could be brought to bear, and with its aid we should be enabled to depict the more delicate and subtle processes of vegetable growth. Such optical studies would be not merely instructive in the ordinary sense of that term, but they would be likely to throw new light on biological problems of the deepest interest. For we are here concerned with changes which can not be directly observed, and whose nature can only be imperfectly apprehended from a comparison of ordinary photographs taken for the purpose. We know, for example, that common instantaneous views of men or animals in motion convey a most imperfect idea of the actual movements involved in walking or running; and a similar remark would doubtless apply with greater force in cases where the pictured objects were undergoing changes of a complex physical nature; so that the human eye, aided by the sensation of motion, might well succeed in bringing to light laws or relations hitherto unrecognized by botanists.