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Sept 23d. 1878

Dionæa— Oscillations(All about oscillation)

Kew Plants good

Fixed tapering triangle of paper to one of spikes, standing almost vertically up of youngish small leaf & observed under compound microscope— Petiole not fixed. During During whole day moved it moved backward, as if leaf opening & from window. Between 10º 40' & 3º moved 5/500 of inch backwards, & about 7/500 from window, ie. obliquely. It continued all day & next morning till 6º 45' a.m moving in same direction. I presume modified circumnutation

As formerly with cabbage there was a remarkable slow oscillation in leaf, only (occasionally) mo sometimes with little starts. At 1º I observed this closely & the oscillations backwards & forwards; ie opening were about 1/1000 of in. At 5º P.m. I put wax taper near leaf— but it was not then oscillating, nor did it oscillate for some minutes showing not due to currents of air but after about 10' when warmed (for my study was rather cold) it oscillated conspicuously & quickly, which Frank saw. It Candle removed & it then ceased to oscillate. But in the course of about 1º 30' was again found oscillating, though not warmed in this interval. Sept 24th at 7º 15' taken to Hot House, which was then cold, & fire lighted. Temp at soon rose to 84º F & when when observed oscillated, but not so strongly as on yesterday.

This leaf sensitive, for when on 26th sensitive filament touched close quickly.

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Sept 24' 1878

Dionæa oscillation oscillation

(Pot taken into Hot-house — filament with mark fixed perpendicularly across another & much younger leaf with Closed blades of which stood standing at right angles of Petiole from not being expanded: observed in Hot-House- (temp 84º-86º F) with light only from above.

This was plant of which complete description of figures.

Micrometer scale 1/500 of inch. At 10º 55 moved quite gently with no starts from me to distance of 1/500 of inch; before this had been oscillating rapidly.

At 11º 10' rapidly oscillating obliquely to & from me by starts of 1/500 of inch, & sometimes 1 1/2 /500 — also at same time laterally. I believe apex describes minute ellipses. At 11º 20' oscillating much less — Looked again often & always more or less oscillating. At 2º 20' I saw sudden start or protrusion of 2/500 of inch. The spectacle is an extraordinary one & movement & very conspicuous, for the micrometer divisions are large—

[insertion:] The appearance always called to my mind an object endeavouring animal endeavouring to escape from [illeg]

The apex of mark quickly darts forwards & then withdraws more slowly. On one occasion in exactly 1' the point made four darts forwards, but besides these, in retreating & advancing, there were many minute minor oscillations backwards & forwards.

The general course of point apparently) to me, & then to left & then from me, i.e between 11º a.m. & 2º 20'. This makes me believe that the leaf was circumnutating ordinarily, & that this wonderful movement show notion of progress— sometimes moving insensibly insensibly, sometimes by starts & sometimes quite stationary.—

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Dionæa; very young leaf

(circumnutation of)

(A leaf when it is first developed has 2 halves of lamina closed together & pointing to ground.— which whilst still closed rises gradually first to right angle to petioles & then in nearly straight line with Petiole. A leaf with closed blades at right angles to petiole had glass filament, (with triangular marks) fixed to it, externally on one side & movement traced on Horizontal glass in darkness— Leaf 1.2 high, with apex 13 1/2 inches from glass— so tracing greatly magnified & tracing not fully accurate. (Used)

See fig (1) leaf made ellipse between 4º P.m & 6º P.m. on Sept 24'— Afterwards moved moved to right in zig-zag course line, till 11º 45' a.m on Sept. 25th— This due to wings blade by some accident having having wings got outside closed laminæ the wings of the petioles, & as wings grew they pushed the closed laminæ to one side.— Therefore filament was removed & fixed on under side of midrib & new tracing begun at noon on 25th (see fig 2.) & pursued followed till 10º a.m on 26th.

The extraordinary zig-zag line shows circumnutation, but the general movements in one direction due to the raising or straightening of the closed laminæ. There can be no doubt that it circumnutates — Observations made in my study — circumnutation wd have been greater in Hot House probably ↘

[3v]

These observations are important for they render highly probable prove proves that the oscillations described yesterday shows up shows us (as I suspected at time from course pursued) what the intimate nature of the circumnutating movement is.

N.B this leaf is the very same one on which the second & more important set of observation on oscillation were made.— So that oscillations have been observed in an open & sensitive leaf & in a young closed leaf

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1878

Dionæa

Sept. 23d A full-grown leaf, which when subsequently touched closed, but rather slowly had

[sketch] filament affixed & traced on vertical glass, Kept dark, from 9º 30' during 7 hours to 4º 30'—

End of leaf 7 1/2 inches from glass— Hardly moved at all. during during whole time.

Sensitive Filament then touched & leaf closed. The mark then stood to one side, & rather higher. New mark made & observed till 6º 50' next morning, but scarcely any no movement,— So closing of leaf does not induce circumnutation. The little which there was, was perhaps only apparent.— This case Supports conclusion from Drosera, that movement from touch not due modified circumnutation.—

Sept 24th Another full-grown leaf was had filament affixed [sketch] externally, near midrib on under side of partly one blade for leaf not very widely opened— & observed as before but not kept quite dark. First dot 8º 5' a.m 2d dot 10º 30,' a.m no sensible sensible movement in the 2º 30'.— then gave I then gave leaf drop of infusion of raw meat, & traced movement (see tracing) — Kept dark) During first 2 hours moved very slightly up & gave more I then gave more infusion; it then continued rising very little till 10º 50' 7º15 P.m 24th.

But the new dot had been was made at 7º 15' (not more magnified) & by 10º 50' had risen a little (see Tracing), fell a little all during night, & next morning (Sept 25th) travelled to left right in zig-zag line. This lateral

[4v]
[calculations not transcribed]

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Dionæa (old Leaf)

movement due to slow closing of leaf from meat infusion; for by 5º. P.m. on 25th plainly more closed, with marginal spikes inturned. By 8º 50' P.m almost closed. By 10º 45' P.m marginal spiks intercrossed. Next morning Sept 26th at 7º a.m leaf completely closed— Had fallen a little during night, but rose rose again by 9º a.m.

The zig-zagging, between 8º 48 P.m on the 25th & 9º a.m on the 26th indicates increased circumnutation from infusion of meat.—

{Length of Leaf

Distance of and of leaf from vertical glass 8 1/2 inches.

(Plant placed (Sept. 26th. 9º a.m) under Skylight & movement traced—; circumnutates but on very small scale: at 4º P.m

Pot put further from vertical glass viz at 12 1/2 inches & fresh dot made.—

Sept 30th it has gone on circumnutating & is still closed: I think that the circumnutation was increased by infusion of meat, but this not proved.