[141]

Jun 18th to morning of 20th Dahlia─ circumnutation of leaf.

Some tubers in box had thrown up some strong shoots about 2 ft. high. & a young fine leaf leaf was selected, & secured at base of petiole to stick, & observed under skylight under skylight under circumstances here pictured. [sketch]

Temp. on 18th 16 1/2 to 17º: on 19' 17 to 17 1/2.—

See 2 separate Tracings — on 18' descended till 11º 35 & then ascended till 6º, after which zig-zagged & ascended a little during night; course of little arch

On 19th behaved differently rather rather for descended till 5º. 45' & then zig-zagged & ascended greatly during night.— We may conclude under moves greatly, descending chiefly during day morning & ascending at night, but zig-zagging on both afternoons considerably.— Amount of movement very considerable, but it must be remembered observed that lines very oblique in the evening & so greatly exaggerated. in the evening.

(a) The line vertical distances in the lower part of the diagram are most exaggerated, as the leaf at first was pointed at 45º beneath the horizon, & when it sank downwards, the glass filament pointed very obliquely towards the glass.// Nearly the actual distance [illeg] by the apex of the leaf was very [considerable]

[141v]

15 feet, by base 7' inches

inches 31

[calculations not transcribed]

[sketch]