[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 44º 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 8º 12 am to 10º. 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 9º 40' descended altogether 1.7 in tracing or nearly 3/10 of inch really & then ascended till between 3º & 4º then went down, & reascended till 10º. 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