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Sept. 10, 11. 12 1878 Apogeotropism of Hypocotyl of Red-Cabbage.

Seedling partially etiolated tall— Kept in darkness whilst being observed.

Sept 10th A Hypocotyl which was a little curved down through Heliotropism was arranged so as to stand 42° 38° from upright [sketch] & movement traced on vertical glass.— Line very nearly straight until Hypocotyl become quite upright & then circumnutated. —Tracing not worth copying

Sept 11th Traced movement of another seedlings 2 3/4 tall— it was already bowed considerably through Heliotropism & bowed part on Horizontal glass in darkness— only feebly illuminated from above at each observation; the Hypocotyl was placed so as to project only 23° from the vertical.

See tracing it curved up with extraordinary celerity in almost straight line from between 8° 27' a.m to 9° 10' a.m when it was vertical ie in 33' & in about middle of area in which it circumnutated—

As soon as it passed the middle point of this area & before it properly circumnutated went went zig-zag .— Aft It moved so quick that eleven dots at a considerable distances apart were made in 34' — ie at an average of 3'— This celerity almost partially account for line being straight; but not quite so, for afterwards completed 3 very large ellipses in 9°.— No does not account for straightness of line.— Apogeotropism seems an overpowering force annihilating circumnutation —

I tried the movement when Hypocotyl formed only small angle from vertical, thinking that perhaps this wd favour circumnutation; but did not do so.—

As light draws twig to one side in opposition of apo apogeotropism, it is odd that when stem turned from perpendicular, that apogeotropism shd be so overpowering Summation of stimulants.