[72]
(1

Radiation

March 15th bright clear night thermometer ─ 4 C˚ on the ground. Plants exposed from at 8.50 pm & taken in either 9.50 on hr, or 10.50 = 2 hrs. All leaves here mentioned were pinned on 14th or 15th

(Cassia floribunda?) exposed for one hour; two leaves pinned the right way up & two upside down. The leaves fell limp & looked killed at night. Next morning the whole plant all the leaves (pinned & not pinned leaves ) were were quite dead & black & shrivelled except a branch which from being low down was partly but apparently very slightly judging by the eye protected by the leaves above,

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[73]

2

Radiation

Cytisus (pot A) 2 leaves exposed 2 hrs

All leaves are shrivelled & seem dead next morning March 16

Oxalis ortegesii 3 leaves exposed one hr. Two leaves well grown ones at top of plant, & one younger one near base of plant.

Next morning (March 16) all leaves on plant killed

[73v blank]

[74]

Mar 16th — Clear mg. — 3- 4 ° on ground C.

O. acetosella— 8 leaves and one leaflet exposed for 1/2 hr. Next morning (March 17th) 2 pinned leaflets killed with exception of over hanging parts; no other leaves pinned or otherwise injured.

O. carnosa 6 leaves, 1/2 hr:

see p 7. for another exper p. 14. Ox. corniculata

Next morning (March 17) 5 leaves of the pinned ones well browned. One not browned, this was now marked (red wool) & released. No other leaves browned except 4 very young leaves part of the same bunch of leaves as the pinned ones. Three full grown leaves also belonging to pinned bunch of leaves are not brown but hang limply in night position— (marked with yellow wool).

[74v blank]

[75]

(2

Mar. 15th Clear night. -4° C. on ground

Oxalis acetosella 7 leaves Kept open by petiole passed through slit in the cork exposed 2 hrs.

p 9. & preliminary (p 2c) on the 24th

Next morning (March 16) all pinned ones utterly dead & brown, except that on 4 leaflets the tips projecting over the cork were still greenish & not quite so much injured. This cannot be due to other leaves accidentally protecting the edges because the projecting edges of a leaf pinned on a high bit of cork above the general level of the pot show the same phenomenon. CD's general impression was that the seven leaves being all killed represented a greater mortality than the number of not-pinned-killed ones I gathered about 100 dead or browned not pinned leaves. some leaves show that they are injured not by discolouration but by not being able to assume the day position.

The pot is mass of leaves in the pot is certainly large in diameter, but I doubt whether the experiment shows that pinning out has much effect.

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[76]

Lotus jacoboeus 3 leaves, half an hour— Next day no apparent injury to any leaves on plant

Cytisus (pot B)— 2 leaves, half an hour. No injury to any of the leaves.

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[77]

3

Radiation

March 16th

In the morning pinned out the following

Marsilea — 9

Cassia 4 (2 each way)

Arachis hypogæa 4

Oxalis acetosella. 8 whole leaves & one leaflet of a 9th

Oxalis carnosa — 6

Melilotus officinalis 10

Lupinus pubescens 5

Lotus jacoboeus. 3

Cytisus (pot B) 2 pinned out March 14 or 15

Plants exposed between 8.34 & 8.40 pm bright clear night Temp on ground between -3° & -4°C. Those which were to be exposed for half an hour were taken in by Horace & me in very short space of time & all done by 9.8 pm. The hour ones taken in by 9.35— Cytisus pot B was exposed from 9.10 to 9.40

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[78]

4

Radiation

Arachis hypogæa 4 leaves, [illeg] 1/2 hr. -3° -4°C on gr

Mar 16.— Next morning (March 17) all four pinned quite killed & blackened. Two of the pinned are on one plant the other two on the other plant in same pot. On One one plant there are 2 non-pinned free leaves utterly killed somewhat injured. On the other plant 2 killed utterly, one injured. This makes 5 non-pinned free leaves injured. On all both the plants together there are 21 leaves non-pinned free & not injured excluding quite bad leaves. Of these 21 perhaps 4 are sheltered by cork plates. There are therefore 17 non-pinned free & uninjured leaves & 5 not pinned free injured; the injured are therefore 5/22 This is total number of all the free leaves of exposed leaves or 23 pin either killed or very injured. It is a curious thing that all 5 not pinned free un injured leaves are on the same stems as the pinned leaves. There are 5 stems on which no leaves are injured

[78v]

[calculation not transcribed] (say 23 per cent)

[79]

Leonard remarked that the plants with pinned leaves had more of their free leaves killed than the other stems or plants in the same Pot. This seemed certainly the case with Melilotus petitpierreana; (Here also see M.S the pinned suffered most) & I think the cause must be that plant kept motionless & the leaves chilled by radiation are not so bathed so frequently by the surrounding less cold air, as the leaves on branches or stems, which are moved about by each little current. Yet if there is a current, how little more wd the air bathe them if stationary.)

[in margin:] The case does not seem to me hostile

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[80]

(5

Radiation

Melilotus officinalis 10 leaves, 1 hr. Temp -3 to -4 ° C. Next morning (March 17) all the pinned leaves injured & none of the not pinned (or perhaps one or two young leaves out of the whole large pot) injured.

All the leaves unpinned & marked as follows.

Red wool Rt hand leaflet 2 & inside half of terminal T leaflet which rested on cork injured

[sketch] This leaflet was pinned

L hand leaflet & outside half of T not so much injured.

This look as if resting on cork caused injury

Red & Yellow. Rt & Terminal were pinned & are injured

Left (1) not pinned & is not injured. I don't know how it went at night.

(showing that the parts which rested on cork much injured in 3 cases out of 10)

(Keep)

Red & green Rt & Terminal not pinned & injured

Left not pinned not injured

Green or Orange 3 leaflets Killed

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[81]

Lupinus pubescens. 3 leaves one hr—

Next morning (March 17) all 3 killed but so many killed on rest of plant that it goes for nothing─

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[82]

(6

Radiation

March 16

Cassia: (common-greenhouse Var.) A second Plant Exposed to temp of -3° -4 Cent for 30.' on early night of March 16. The 4 pinned out leaves with every leaflet quite dead & both upper & lower surfaces completely blackened.

On whole large bush only 7 other large compound leaves blackened, & only one A of the 7 with both surfaces blackened & this was a younger leaf than any pinned down: The following case good

[sketch] A B C D Branch z

on branch (z) the uppermost young leaf A free & with leaflets blackened on both sides, as already alluded to.

B & D pinned down & with all leaflets as black as ink on both sides. The intermediate leaf C. free & badly injured, but the lower surface still retaining some green tinge. It is remarkable that the leaves when asleep expose their lower surface [5 inserted words illeg] & yet it is to & not [illeg] ; [illeg] it owing to an upper [illeg] when we [3 words illeg], when any upper which is most blackened; is this due to mere difference cd [2 words illeg] a2., not what was to to [3 words illeg] any chlorophyll or more tender. or owing to its more [2 words illeg] we do not know.)

p 13 Cassia

p 14 floribunda & lævigata

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[83]

(7) 1

Mar 24. Sky clear calm

Temperature on dial from 25-26 3°.3 to 3°.8' falling to 22. Fahr

Exposure 35'-40' minutes except Ox corniculata which was 1° hr out.

O. carnosa whole plant killed & a 2d species

Arachis hypogæa Pot II — Three leaves pinned close injured

26 free leaves injured [+] 18 free not injured [=] 44

[calculation not transcribed] ∴ 26/44 of the free leaves were injured, all the pinned injured.

Arachis hypogæa Pot I 3 leaves pinned 2 of them on tall pins one close to cork — all 3 killed. Four leaves had each one pr of leaflets pinned fastened out by paper & gum. All four quite killed (including a pr of leaflets that could sleep on each leaf).  Of the free leaves 10 quite killed, 2 almost (and 12 unhurt) Among the free leaves were 2 or 3 half injured ones exposed March 16th — We might say half of the free ones injured — all the pinned ones injured—

As a grand summary we may say 1/2 free killed or badly injured 6 Pinned all Killed

[83v]

Mar 25

Arachis 1° 30' -2° C. not injured

23d Arachis for 30-35m — 2° C. not in the les injured

[84]

Cassia ─ two leaflets leaves pinned on tall pins. 1 ─ pinned flat close} whole plant killed

Cassia florida — (young) seedling all plant killed

Cassia lævigata all [plant] killed

Oxalis carnosa— all [plant] killed

Cassia

(p 8 p. 2.)

Melilotus taurica 25°- 26°F & (-3° to -4°)

6 pinned tall pins3 pinned close} 9 all all generally killed

Exposure 35' to 40'

Free ones about 80 killed & 130 130 not killed or 8/13 80/210 or 8/21 rather more than 1/3 killed

(The tall pinned & close-pinned equally killed)

Melilotus macrorrhiza. 2 tall pinned 5/6 killed 2 close pinned} all killed equally

1 paper gummed killed

1 ditto — not killed

I saw that the not killed one is prevented from sleeping by the paper/

About 50 free ones badly killed & perhaps 20 injured— Between 100 & 150 free ones uninjured ie about 1/3 free ones injured

1/3 of free killed

Melilotus petitpierreana? all killed

6 tall pinned 4 0close} all killed

The close pinned are rather worse killed as there are patches of green leaf on 4 of the high pinned leaves.

[84v]

[calculations not transcribed]

[85]

(9) 3

Exposed Mar 24 (see p. 1 for Temp.)

Melilotus-petitpierreana (continued) (This plant seems not to sleep at all well)

/ A good many free leaves drooping & shrivelled & most of the budding "leading" shoots are killed But I think there was certainly less injury than in the two last pots

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[86]

(9

3°.8° 3° 3 to 3°.8

(March 24th)

Oxalis acetosella Temp. on dial 25—26 F. falling to 22° or 5.5

exposed 35'—40' — 5 tall pinned 3 4 flat close pinned + 1 leaflet → one of the close pinned is really gummed with paper. — of these 4 tall & [illeg] one close pinned are killed that is 30/48 = = 5/8ths of the pinned are killed.— ie 63 per cent

Free leaves about 20 killed & 20 or 30 more injured— Between 200 & 300 leaves in pot. Say 8/48 = 50/300th = 1/6 1/5th of free ones injured

20/250 : 2/25 [4 words illeg] ie 8 per cent Killed

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[calculation not transcribed]

[87]

10

Feb. 1' Radiation

Melilotus Italica, officinalis & Trifolium resupinated exposed for 6° to 10° 30' to clear sky & slight frost, pinned open leaves next day apparently not at all injured.)

(Feb. Feb. 6 & 7th Melilotus officinalis & taurica & dentata & Lotus & aristata put out at 5° 30' — sky clear. Temp on grass 29°.

(N.B. Mel. officinalis — one leaf which was pinned open so that lower surface exposed is much injured, whilst 2 others apparently are not so.) (Mel. dentata, no leaves injured.)

(Mel Lotus aristata; 2 of the pinned open leaves more injured than those above & below on same branches.)

(Feb. 8th Mem. officinalis & dentata same leaves again exposed from 3°: 30 to 10°. 30' I suspect all the pinned leaves have suffered most:

Feb. 12th some leaves all over most of the plants in whole large pot Killed, but all 4 pinned— open leaves Killed, & I think rather more injured than any of the free ones, especially one so pinned that upper surface exposed.

Finished

M Taurica (over)

[87v]

Radiation

Melilotus Taurica Jan 25th exposed from 5° 30' to 10° 30' P.m. sharp frost sky clear slight wind. (Compare the pinned open leaves with those on branches tied with white wool, for most of leaves were vertical on these branches) N.B. Cork wd retain heat for some time & check effect of currents of air on lower side of leaves. This plant was afterwards turned out for about same time on clear frosty night & the 5 pinned open leaflets certainly seemed to suffer most more than others above & below on same branches.

Vegetable marrow (Used) — Jan. 25' seedlings too old. Cots did not close much— tied some together — Kept one with cots wide open.— bowed 2 to one side; some left with Cots slightly gaping & upright & exposed from 5° 30' to 10° 30' (see under Mel. Taurica above) — (Threads & wire will show which were treated & in which manner.)

Jan. 28' all leaves whatever rotted & decayed.)

Feb. 8th (Veg. Marrow (Used), exposed more, 4 fastened open with Hair-pins, 3 with Cots tied together exposed from 7° 23 P.m. to 8° 38' (28° F. on Pot) ie for 1° 15' (see paper for temp.) with apparently (Feb. 9th 8° a.m) no effect.

(Feb. 12th only 1 injured & this now utterly dead & this was one tied so as to be closed; opposed fact.)

Finished

(over)

[88]

11

Radiation

1878

Feb. 6 Melilotus italica 3 leaves pinned with upper surface (White W) 3 leaves with lower surface upwards (black wool.) — sky brilliantly clear at 5° 30' grass 30°; at 9° 30' temp 28° exposed from 5°. 30' to 10° 30' P.m. All six leaves much more injured, as seen next day in greenhouse, those that other upper leaves which went to sleep & were nearly vertical, though some of the rather older leaves were a little spotted.

Feb. 8th. The several leaves which were pinned open seem much more injured, (some appear as if infiltrated) than the free leave, though several of the latter are injured; especially the young ones. — It is not possible to whether those which had upper or lower surface exposed are most injured.—

Feb. 9th I am doubtful whether pinning has produced much difference, so many other leaves injured

Feb. 12th Leaves on 3 stems in same pot pinned open.

Stem (1) the 2 pinned open leaves more injured than those above & below on same branch

(2) the 2 pinned open more injured than a younger leaf above (& the younger ones generally suffer most), but some below are more injured

stem (3) All the leaves on whole stem much injured, but one of the 2 pinned open more injured than any on whole stems.

(Finished)

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[89]

12

Radiation

Feb. 8th Trifolium resupinatum, exposed from 6° P.m. to 10° 40' (see paper for temp) several leaves some pinned with upper & some with lower surfaces exposed.

Feb. 9th I cannot make out yet which most injured, both pots badly depends much on age.

Feb. 12th whole plant Killed, no conclusion possible.)

O/ [Darwin's shorthand for 'nothing new']

Feb. 8th Melilotus suaveolens with several leaves pinned open with upper surfaces exposed for time as with Tri. resupinatum.

Feb 9th & 12th no marked effect

Feb 8' Mel. dentata (as last sp.) upper surface alone exposed─

Feb. 9' & 12th— no marked effect

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[90]

(13

March 25. 78 Clear night— some wind

Temp. on grass. —2 C° about 9 pm; at 11. on dry ground─ 1.5C° and temper. of air sheltered ditto

Cassia calliantha (?) exposed for 60' no effect (not injured)

Marrow 1. 30' do (do)

Trifolium subterraneum 1. 30' do not injured

Oxalis corniculata 2 Pots for 3° till 11 pm — do not injured

Oxalis valdiviana 1°. 30' — not injured

? Amphicarpæa (seedling) —1° 30' 1 not injured

(Cassia pubescens (seedling) 1° 30' 2 not injured)

Erythrina cristagalli 1°-0' not injured

Arachis hypogæa 1°. 30' not injured

Cytisus Canariensis (2 pots) 2°─ 0' 5 not injured

Melilotus suaveolens 2°—0' injured see note

dentata) note back 2°—0'— un not injured

I noticed decidedly more frost on the close pinned leaves than on those on long pins of M. dentata

Very important

M suaveolens olins 4 right way 4 upside down} all close pinned

Dahuria, Spengler Steudel (see Back) Very important

Of these 3 upside down 3 right way up} were quite limp Mar 26th AM & I think dead

The only free ones uninjured and were 2 or 3 little young ones — Large Plants with a multitude of (about 150 leaves) leaves

(over)

[90v]

4°. P.m. 26th only a few of these leaves now look slightly limp; the others seem recovered — about 15 leaves on these plants.— 27' 12°. noon— It is all a mistake — 3 of the leaves are a little more limp than the others free ones, but very slight difference not worth notice

[91]

14

Radiation

Mar 23d — Exposed to -2C° (on earth Sky perfectly clear.

Cassia floribunda 40' minutes

lævi vi gata 35'

Marsilea. 1° 35'

Cytisus Canariensis — 1°. 35

Lotus jacobœus— 1°. 35'

Oxalis pierrii— 40 35'— or 40'

Arachis hypogæa 30' or 35'

Oxalis carnosa. 30' or or 35

O acetosella— 30 1°30 30' 1° 30'

Oxa 3 Melilotus plants of different species 1° 25'

Oxalis valdiviana (seedlings) — 1°

Oxalis corniculata (2 pots) for 2°

Melilotus macrorrhiza — 2°

Amphicarpæa — 45'

Seedling Cassia 2 Pots 45'

Veg. Marrow Pot I 45'

─ Pot II. 1°. 30'

[in margin:] Some leaves pinned to cork & some 1/2 or 3/4 inch above cork: Not one in the least injured from stated periods of exposure

[91v]

[calculation not transcribed]

[92]

March 25th — Sky clear— calm— Temp on dial at commencement 25-26° F falling to 22° Fahr.— Vegetable Marrow (Used)

Two pots of seedling Veg. marrow exposed for between 35' & 40'

Hardly The Cots. of seedlings from being rather too old did did not close perfectly, so 6 were tied up with bit of wood with tips as usual reflexed & of these .5 (ie 5/6) Killed.

Six other seedlings had cots. kept horizontal by wires, & of these 2 Killed ie 2/6 Killed. [sketch]

This is an extraordinary & inexplicable case as supposing my theory quite wrong, yet why shd. standing upright with Cots. close be more fatal— I can only understand it by supposing lower side of Cots. more tender.— We may conclude that Cots do not close to protect themselves from radiation.

[92v]

We were are surprised that the young seedling of so tender a plant as more [illeg] were all the [illeg] as well as of bud expose to a night for 11 45' on a freezing night, with the [illeg] as in [illeg] at 29° F. It may be added that seedling of [illeg] the [illeg] C. pub was fr 1. 30 to a clear sky all the length of the temp grass -2°C. without the least injury