[92]

1878. Action of different degrees of Light at different distances.

Phalaris— too old seedlings

Sept 21'— Hall-lamp — in Frank's room darkened completely.

Pot (1) 2 ft from middle of lamp. Pot (2) 4 ft. Pot (3) (too bad seedlings to trust) (6 ft) — Proved by Plumb-line that stems of 2 seedlings in each pot, vertical, Started at 9º 7' a.m — after 1º certainly no effect— Possibly in 1º 27' the 2 in Pot (1) slight curvature. After 1º 50' the 2 seedlings in (1) almost certainly curved & the right younger Seedling in (2) — Aft 2º 13' no doubt that both in (1) & both I believe, (certainly one) in (2) curved — After 2º 41' one can see without aid of plumb that tips of all 4 seedlings in (1) & (2) curved yet those in (2) received only 1/4 of light of those in pot (1).— After 5º no doubt that seedlings in (1) more curved than in (2) & no doubt from former experiments that plant seedlings in (1) wd. havebeen very much more curved, if they hadbeen exposed to bright light.— no effect in Pot. 3 but these seedlings bad. At 3º P.m. after 5º 45' same state of things, but when I looked after addition 1º 30', (i.e at 4º 30') lamp gone out.— & I believe apogeotropism had made seedlings more upright. in Pot (1) angle of chord

20º from perpendicular 11º —} mean 15 1/2º

In Pot (2 — 14 1/2 4º} mean 9 1/4