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March 7th–11th 1878

Plumbago Capensis

A small lateral branch, projecting standing about 35º above the horizon & growing freely was selected for observation & some of the upper branches having been cut away, a filament was fixed transversely across it near its summit tip, & the movement of the bead traced on Horizontal glass.— Plant illuminated very feebly from above.

Tracing magnified 13 times. The branches never showed any tendency to turn upwards from apogeotropism; but for For the first 11 hours it moved to a great distance greatly in a nearly straight line to one side from some another cause ; probably owing probably to its having been deflected by the light whilst standing in Greenhouse, had been drawn to one opposite side by light. At 7º 20' P.m on March 7' a fresh tracing was began & continued during (see fig) & for about 2 hours it followed nearly same course, then & then bent to oth changed its course it a little; & during the night it changed its course completely, & moved at nearly right angle to its former direction. Next day (March 8th) one zig-zagged greatly, & so it did the following day (9th) till about 3º P.m by which time so the tracing figure had become so complicated a figure had been was described that it could hardly be copied accurately. & no more dots were made. But It continued moving to mo in the same manner round & round over a small space during during the whole of the 10th & morning of the 11th turn round & round over the same small circular space — The movement was small for the spaces swept in a sl moving line over repeatedly between 3º P.m on the 9th to the early morning of the 11th was a circle of only 1/26th (.038) of an inch in diameter, & the tracing ought to have been magnified thrice as much for the movements of the bead to have been accurately followed; but from the zig-zag line previously formed & the figure described, the stem no doubt circumnutated.—

For tables of times see old M. S with Pelargonium.

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[calculations]