(1

Dec. 3d

Canary grass — Light Exposure

8° 5' a.m put in S.W. window, very dull & misty morning & day; pot with young seedlings — sides & top sur with books so that dull light come in only on one side—

(I slewed pot round — relatively to position which it had held whilst caps were put on.— I put 3 with caps of tin-foil darkened & with tissue paper moderately closed below with black card round bases on ground so as not to reflect light upwards. At 1° 2 10' P.m quite vertical; the third curved but not parallel to the free ones; on examining the tin-foil when opened there were 2 minute punctures, but I do not believe cause. I remember one was bent when I put on cap, & I suspect it was merely further bent by weight of cap) (a)

(1 with conical, inside glittering, cap & no card below: this was vertical: on the day when the seedlings with such caps were bent, the sun shone & much more light wd be reflected upwards.)

(1 with gum & manganese on very tip & black wafer, just covering tip the black wafer slipped on one side. This seedling was well bent to light, but on removing the black crust, I found on side of stem which was concave, several minute bubbles of dried gum, which were quite transparent like glass, & I do not doubt that light was transmitted through these holes, which were excessively minute.

(In the pots there were 19 plants altogether, & every one of them were strongly curved, so that upper portion almost horizontal, except the 2 with blackened caps & the one with conical internally shiny cap. There is only 1 which gives any doubt, viz the one with blackened cap which pointed obliquely to others, but towards light.

(The plants are from 6/10 to 9/10 high, with a few shorter. These plants consist of a sheath flattened purplish, with flattened soil tip of white colour, & pointed cells; seem growing point. — a little way down within this sheath, there is young pulpy involuted leaf— How leaf escapes I know not.—

[1v]

2° 50' The 2 which had caps & were vertical are now decidedly curved towards light.—

4°. 25' The 2 which had caps & were originally verticals are now as much bent or very nearly so, as the others !!! The one with a cap which was bent obliquely now faces to light, in line strictly parallel with all the others.

No I find this remarkable difference between those which had caps & those which had not, namely that the latter are abruptly bent near base, whereas those from which caps removed are curved equally from the tip to base. I presume that this occurred at first with those which never had caps, but as soon as tips faced light, the terminal portion straightened itself.

[slip of paper pasted on, specimens]

cap removed 1°10'

never a cap

The above plant was kept in darkness till 9° a.m next morning Dec. 4 it was then nearly vertical, but not quite

(2

Canary grass— Caps of Tinfoil

Dec. 4th The same pot as yesterday's, the seedlings still crooked & pointing in many ways even 2 of the 4 now with caps. Put on caps under bichromate — Placed pot so that none of seedlings pointed to the light.— Pinched bases of caps & put black paper beneath

(Exposed to light at 9°. 45': at 4°. 30' P.m. examined, there were 8 with no caps, all greatly bent, especially towards near bases, (but not angularly there) in direct line to light. The 4 with caps not at all affected, some still bent in one direction & some in another 2 tolerably upright.

Dec. 5th I have now measured the 3 caps of ordinary make (for one was new bad plan) & they were internally .15, .15, & .19 in depth & these sufficed to prevent any bending.)

Dec 5th The seedling which had caps on yesterday when at had 10° 30' a.m their caps removed & exposed to paraffin lamp at 5° 15' P.m all 3 were well turned to the light.— shows not injured or pinched

Tin Caps may have pinched

(good)

(3

Dec. 7th

Canary grass. Caps good case

Four seedlings all about 4/10 of an inch high, some a very little more, & some a very little less high, had caps of tin-foil— blackened within & black-paper on soil, exposed to paraffin paraffin lamp at 10°. 45', a.m & removed from lamp at 5° 15' P.m.—

No' (1) Cap internally .1 of deep, plant vertical

N' (2) cap internally .15 deep plant quite vertical

N 3. cap internally .15 deep do do

N 4 Cap only .08 deep do do} There were 13 other plants in the pot & all these wonderfully bowed to light, so that upper part of some almost horizontal, light having been on a level with top of plant pot.

This latter most important observation, as it shows that early age sensitive zone not deeper.

Specimen of the bending} [Specimens]

Did the caps pinch & act as if tips cut off

(Dec. 8th These plants had caps removed & exposed to light & all became greatly bent, showing that sensitive.) & not injured

(Dec 8th a seedlings .31 in height had cap .07 in internal depth, exposed from 9° 30' to 4° 30' to light & become slightly bent, so that sensitive surface of young plant extends deeper than .07.)

Caps often act do they prevent plant bending

Reddish Sheath grows to length of 2 inches above ground

(4

Dec. 8th 1877 (Two youngish plants had rings of blackened tinfoil placed round upper end, which fitted moderately close, with black paper on soil, with .05 of tip exposed— These were exposed to lamp at 11°, they were a little curved to light at 2° 30', & as much curved as other plants in pots at 4° 30'. This proves that tip is sensitive to light, unless light got in round upper edge.) Paint

Dec 9th The bandages were slipped up till white tips alone exposed to L. light for 7° 15; one quite upright; the other of which tip had grown a little was I think a trace curved to light, for next morning seemed quite straight. These 2 trials make me think that white tip not sensitive to light.

(Frank & I coloured with lamp-black & gum 7 seedlings leaves about tips curved but in most of cases bubble had formed leaving transparent spaces in crust & few of experiments can be trusted: these may be quite rejected.

(1) tip for .05 not painted, paint extending down from tip to .25; the paint a thick crust, a rather moderately tall plant 1.05 high not curved, exposed to L. for 6° 30'

(2) Plant .85 high, tip .05 left naked, paint extending down for .25 slightly curved & next morning straight— this

(3) Plant .7 high, tip .05 left naked, paint extending to .2 from tip., slightly curved, next morning straight

(4) Plant 1.14 high, tip .05 left naked, part extending down .2 from tip not at all curved to light.—

These exper. indicate that with young plants tip of .05 in length slightly sensitive to light, but that plants just above 1 inch height have their tip of .05 in length not at all sensitive

[109]

Pot 2 Lamp 10° 50' removed 5°. 15' [+] 10 [=] 25 (6°. 30')

(1) not curved .05 .25— taller — thick crust

(2) somewhat very slightly curved thickish crust short plant only .5 .25 exposed; next morning straight

(3) do slightly somewhat curved .05—.2 — ↖ do .7 of tip now exposed next morning straight

(4) hardly at all curved & taller plant .05—.2

(Painted seedling)

[Right margin:] Dec 4th

Pot 3. same about lamp.

(5) (6) (7)} all slightly curved, even one with only white tip exposed — do not look so thickly painted

Next morning crust not very thick — These are all still curved to light except tips, whilst other plants are straight. This very odd were they curved before or does black crust somehow prevent them growing straight again?

On (1) crust very thick

No 5 Rt Crust full of Holes

N. 7. also Holes in both spec. more on one side than other

No 6. do

(Try painting & geotropism)

[109]

The Surgeon of a whaling ship assured me that when the Pediculi, with which some the Sandwich Island natives on board swarmed, strayed on to the bodies of the English sailors, they sia in the course of three or four days & were found adhering to their clothes. These pediculi were darker coloured & appeared different from those proper to the natives of Chiloe in South America, of which he had collected & gave me specimens.

[Draft of Descent 1: 219-20: "The surgeon of a whaling ship in the Pacific assured me that when the Pediculi, with which some Sandwich Islanders on board swarmed, strayed on to the bodies of the English sailors, they died in the course of three or four days. These Pediculi were darker coloured and appeared different from those proper to the natives of Chiloe in South America, of which he gave me specimens."]

(5

Dec. 13th Pipes — Canary-grass Pipes of tinfoil [illeg] — blackened within, slipped over & then pinched laterally, cracks filled up (leaving tips exposed) with Indian ink & black paper on ground. The plants in both pots were all slightly inclined in opposite direction to light.

(1) Plant .75 high— tip .04 exposed. Considerably curved, young leaf grow out of tip

(2) Pl. nearly .6 high— only white tip exposed: somewhat curved, coloured tip .04 in length now protruded & tip of young leaf protruded —by — tip itself curved

Rather good

Perhaps Pinched by tin-foil

See back conclusion

(3) Pl. .6 high .05 tip exposed: perfectly straight, but tip itself a little curved

(4) Pl. .55 high .05 tip exposed; slightly curved, but not quite in direction all the others —top of pipe rather open — tip itself curved

(5) Pl. .75 high— white tip alone exposed: perfectly straight or rather whole stem inclined a little from light, as it was before & tip of protruded young leaf quite straight

(6) Pl. .55 high .05 tip exposed: extremely little curved, but tip itself curved

(7) Pl. .45 high .05 exposed: perfectly straight, tip & blade tip of young blade — whole stem inclined a little from light, as it was before

(8.) Pl. .55 high .04 exposed: inclined as it was before exposure to centre of pot & not affected by the light

None of the curved & protected plants, nearly so much curved as the many others in the 2 Pots.— Pot with 1-4 exposed from 8° 45' a.m to 5° P.m.— Second pot with 5-8 exposed from 9°. 40' to 5° P.m

expose 8°

(over)

[5v]

Conclusion— that the tip for upper .05 is slightly sensitive to r light, as shown by its being occasionally bowed, but has only slight power of causing whole stem to be bowed.— It is very doubtful whether extreme white lig apex is sensitive. The upper .05 in the younger or shorter plants often fails to act at all on the stem. I think these conclusions agree pretty well with the doubtful one from painting with black.

(6

Dec. 14

Canary grass—Pipes of tin-foil Deep Caps. Too Heavy plants bent & already crooked (Placed before Lamp at 9°— Removed 4°. 45')

(1) Pl. .8 high. cap .1 deep — plant slopes a little towards light (Much curved to light.) but not quite straight to light. It looks to me as if weight had carried down stem) Dec. 15' 8° 15' all about all the free plants in pots almost vertical, but No 1 with Cap as much bent as before, I believe weight.

(2) Pl. .95 high cap .25 deep. (slightly curved) Dec. 15 8° 15 quite straight, so I suppose was really acted on: I can see no chink for light— Cases inexplicable

(3) cap Pl. .75 high cap .2 deep (Very considerably curved) Dec. 15th 8° 15' as much curved as ever I suppose weight of cap. — This very hostile fact goes for nothing

(4) Pl. .9 high cap .19 deep. (Vertical) Dec. 15 8° 15 still vertical.

(The 2 plants covered by silver paper, come with tips curved towards light)

Dec 15 Case (2) is the sole anomaly.

Examine caps tomorrow (Tin Foil)

(7

Dec 15th (18'?)

Canary grass Deep caps I suppose tin-foil

Lamp. Window S.W at 9. 35 from first seven all removed at 4°. 40'

(1) Pl. .95 10 inch high: cap heavy .1 deep: slightly curved to light

(2) Pl. .9 8 high: cap heavy .25 deep slightly curved far less than former one

This case a great anomaly

(3) Pl. 1.15 high: heavy cap .2 deep: vertical

(4) Pl. 1.05 high: heavy cap .17 deep very slight curved

(5) Pl. 1.05 high: light cap .1 deep: slightly curved

(6) Pl. 1 .8 in high—: light cap .19 deep. vertical

(7) Pl. .95 1.1 high: light cap. .19 deep. vertical} great contrast with those without caps

[Lines erased]

2 Conical caps with white paper

[Slip of paper pasted on]

3 black cards (1) pl. had slided round corner, no doubt lamp side of room more illuminated (2) pressed firmly against card. (3) very slightly curved yet this was one with hole in card. Blacked inside of pill- box [sketch?]

[7v]

(8) Pl. .65 .9 tall — light cap. .13 deep vert Vertical

(9) Pl. .12 1.1 high light cap .15 deep very considerably curved, but curved to one side not parallel to all other — weight. No Dec. 19' 8° from growth of enclosed pot cap covered only .06 of tip of sheath & no doubt this caused the considerable bending

(10) Pl. 1.2 8 high cap .2 deep slightly curved. Dec. 19' 8. a.m. very considerably curved, as much as any, so that I presume weight—

(When I give my experiments, state liability to error from weight of caps & the necessity of greatest care that no light admitted.)

Examine depth of caps of those not affec which are curved

(8

Jan 1

Canary grass Light

exposed from 9° to 4° 30' to paraffin Lamp

(2d pot beginning with no 13 from 9° 40 to 4° 30)

(1) (2) (3) Seedlings close about 3/4 inch high painted from apex to .2 down. All 3 curved slightly to light —

(Jan 2nd 10° 45 a.m. have become vertical) This fact shows well how sensitive to Light as can act through 2 coats of thick Indian Ink—Nothing but thick crust of black mud will serve

Painted Indian Ink & Caps of Tin-foil?

(4) & (5) Caps .2 Quite upright vertical

I suppose tin-foil

(6) cap .17 deep Quite vertical

(7) Cap .2 deep, Quite vertical as far as direction of light concerned, but cur bent at rt ∠ to it Jan 2d 10° 45 a.m still in same position

(8) cap .18 deep Quite Vertical

(9) cap .12 deep Slightly curved, & rather obliquely to light (Jan 2d 10° 45' a.m. same position)

(10) cap .16 deep slight curved in direction of light but almost at inclined almost at rt ∠ to direction of light (Jan 2d not very well closed at base)

(11) cap .2 deep Quite vertical

(12) cap .1 deep somewhat curved, but not nearly so much as the free seedlings

(Jan. 2d 11° a.m. now parallel to most of other free ones)

(13) cap .25 deep Quite vertical

[8v]

Canary grass — Same Pots—

Jan 2d. Lamp 11° 30' a.m & removed at 5° Pm

A. & B. Pipes only white tips exposed (A above 1/20th has grown out & whole seedling slightly curved to light) B very little has grown out, but yet slightly curved

(C) Pipe leaving only .15 exposed— perhaps too stiff to allow of movement

Exposed part alone curved— the pipe part upright

D E & F whole basal part & tip for 1/20 painted very thickly zone of .1 below painted tip left unpainted— All 3 perfectly vertical. This very odd I doubt whether but I believe after some comparative trials is due to rigidity given by 2 or 3 coats of Indian ink mud.