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Sept 5th 1878 Tropæolum majus (Heliotropism

A young seedling, with 2 first leaves hardly expanded.

Observed from 10° 11' a. m till 7° 20' P.m before N.E. window like 2 previous cases. Until 11° 40' moved very straight straight— Then until 2. 24' clearly attempted to circumnutate. See Tracing C. almost making one considerable circle: After 2°. 24' resumed its course towards light, but in rather zig-zag line. At 4°. 26' left horizontal glass & at 4.58, mark was on vertical glass, & continued to travel to light until 7° 20', though it was then dark— Clearly modified circumnutation.—)

(Heliotropism with very obscure light)

(Sept 7th. Same older seedling stood in same place. ie 39 inches in front of N.E window, with the 2 other windows in same room, & was observed with very obscure light coming through the window & with towels &c thrown over it.

[insertion:] (protected on each side from all light by blackened paper)

Light thus affected plant on 2 opposite sides, stronger on one than other side. See Tracing D.— First moved to light: at 8° 51' cotton blind pulled down with muslin blind behind. As it continued to move move to light, from 9° 13' to 10° 30' pl (ie for 1° 17') shutters were shut or plant entirely darkened; & it immediately circumnutated in a circle.— Shutters were then opened, blinds still down & one or 2 towels with & sometimes another muslin blind placed between window & plant. The towels & muslin blinds were varied because sky was sometimes bright & sometimes cloudy. There was always some light from window more than from part back of room, as shown by a slight shadow being cast from an upright

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Tropæolum majus — Heliotropism

pencil. Plant kept in this exposed to this very dim light from 10° 30' to 3° 3 (i e for 4° 30', & during this time made 3 irregular circles, but did not move did not stand at end nearer to light than at first, so was kept too dark. From 3° 3' to 4° 30' blinds were still kept down, but nothing else was interposed, & during this time stem made 1 1/2 circles & moved nearer to light.— At 4° 45' as evening had commenced, blinds pulled up & then stem moved at in zig-zag line to light & so continued till 6° 45', when apogeotropism prevailed & plant moved from light in zig-zag line still circumnutation.

By 10° 40' P.m had gone as far back as it desired, for stem stood on same level with respect to the window next morning (8th) at 6° 45' a.m, having been kept dark all the time. The course whole course during whole day from 8° 51' a.m to 10° 40' 6° 45' P.m may be considered considered as one of due to circumnutation, slightly modified by more light having having come come in through N.E window than in any other direction.)

6 or 7 ellipses