[88]

Sept 19. 1878 Phalaris Effects of brighter & duller light

A pot was placed in S.W. window— Bright morning, but become cloudy as day advanced; & another another pot in same position with towel over & 2 muslin blinds—But the muslin blinds were removed after 30' The plant in this pot circumnutated for first first 45' & then proceeded direct to light— At 12° 5' began to circumnutate; so that this plant behaved like the ones (spatial tracing is given) exposed & uncovered to fairly bright light, & began circumnutating at exactly same time; ie about noon. But there was this difference in the two cases that the dim light did was not sufficient to modify circumnutation start the movement so soon. — other pot began to go straight in 30' I have not thought it worth while to give tracing of plant behind towel. In evening at 5° P.m the plants in the 2 Pots— did not differ much in the degree of curvature to light, perhaps some of those that exposed to brighter light rather most curved

[89]

Sept 19. 1878 Phalaris Canariensis Heliotropism facing bright Light

Pot with young seedlings placed in dark box before before S.W. window with movements traced on Horizontal glass. — magnified Morning Morning bright sky, but became rather cloudy as day advanced—

First dot (See Tracing Fig M.) as soon as placed in window at 8° 50': as usual did not settle quite truly to its course till 9° 35' (ie in 45') & & then travelled for during 2° 30' in almost [illeg] straight course to light. (In almost every case strong tendency to circumnutate about midday) At 12° 5' showed si a deviation, or even rather earlier & then circumnutated; as usual receding & circumnutating in axes parallel to advancing line as if momentum had from Heliotropism had carried it too far.— After 4° 30' as evening became less bright the backward movement probably in apar part due to apogeotropism.

For Series to be engraved.

Series Fig M. Sept. 19 Bright Light

Fig A. Sept. 16

Fig 2. Sept 14th another form of obscure light