[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 17°: on 19' 17 to 17 1/2.—

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

On 19th behaved differently rather rather for descended till 5°. 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 th diagram are most exaggerated, as the leaf at first was pointed at 45° 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]