[80]

Common Cabbage

(Movement of leaf of full-grown plant in darkness)

Nov. 10th A large plant in pot in greenhouse of which I measured distance of opposite leaves some little time ago, had now run run up a little so that head not so no longer compact. Chose One one of young leaves on the summit, (within which several smaller leaves,) 5 1/2 inches in length, & inclined 44° above horizon. I fixed long glass filament to mid-rib with little mark with black dot at base, so that I could look along it & make dots on vertical glass; Kept in complete darkness. From distance of glass angular movement increased about 6 times, proport 6.17 say 6.2 times but of course the higher part of tracing more magnified than the lower parts. During first day moved steadily up, ie closed, from 8° 12 am to 10°. 53' P.m. As the tracing is 4.1 inches in length, the actual the movement must have been little less than 1/6th of this. During night descended a little or opened, & continued to descend till 9° 40' descended altogether 1.7 in tracing or nearly 3/10 of inch really & then ascended till between 3° & 4° then went down, & reascended till 10°. 50' P.m. During the night descended a very little & in the morning began to ascend. Movements becoming feeble from continued darkness.— We may conclude rises or shuts during day & opens or expands during night. The great upward movement during first day, probably due to leaf having bent down during several days from incidence of light in greenhouse!—

[in margin:] All these measurements must be remade on the tracing