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Sept 9th 1878 — Red-Cabbages seedling— Heliotropism of Hycotyl. obscure light.

Filament fixed longitudinally to Hypocotyl.

Right-Hand seedling. (Tracing I.)— Plants placed a yard before N.E window with blind & muslin blind drawn down. Traced with & towel & hung over.

Day rather foggy & cloudy, & when when it grew brighter for an hour & 1/2 an additional muslin blind thrown over — Thus light nearly uniform yet yet very dull light — Other windows in room not obscured — Pencil threw shadow; if we judged by eye it wd have been thought plant illuminated by general light of room.

In afternoon at 3° 30', removed towel & substituted muslin blind, & at 4° as evening evening came on muslin removed. But the cotton & muslin window blind never removed. (Used) (These remarks on light apply to both Tracings) First part of Tracing not quite accurate up to 11° 4', as it was before too much magnified, & since was then reduced by eye, & added to later part but general direction of the separate bends true— After 5° 15' began to withdraw from the very dull light.—

(The movement, under exactly same conditions of Left Hand plant (Tracing II.) shows still more circumnutation, but still hypocotyl clearly bent to light. After 4° 23' (ie at 4° 45' filament was found loose) & perhaps probably part of the large movement in straight line between 4° & 4. 23' was due to sliding of glass filament.— In these 2 Tracings we have wonderful contrast with the usually straight movement of from Heliotropism, to ordinary bright light. There can be no doubt that movement in these 2 cases is modified Circumnutation.

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