[416]

Dec. 31. & Jan 1

Common Bean.

Radicle

Bean germinated on sand, turned it upside down so that radicle projected vertically up for .2 of inch in Height; fixed obliquely glass-filament to it .98 long, & traced on Horizontal glass in darkness. The tracing of bead at end of filament, magnified 22.68 times. Traced from 8º. 30' on Dec. 31 to 11º 10º Jan 1' (ie nearly 28 hours by which time radicle had increased 2-3/100 of inch in length & had begun to bow over to one side. The movement is considerable & clearly represent circumnutation. At 5º 12 began to move to left in diagram & continued so to move, but in zig-zag course till till 10º 35' P.m at night— During night it moved far in same course so as to be off glass.— Therefore at 7º a.m on Jan 1' (see tracing 1) a new tracing  begun & falling till 11º 10' & still pursued same course, but as before zig-zag, showing that apogeotropism is modified circumnutation. No doubt this movement wd have continued till end of radicle reached soil.— We Beneath soil the nutation wd be less, but I cannot doubt this movement aid in burying the radicle.—

Used