[91]

Oct 2. 1878.

Phalaris Blackened glass tubes

In one pot First pot put on 6 thin & fine glass tubes with summits black with blackened paper, & disc of black paper on sand at base, & 6 with similar unblackened glass tubes. The blackened ones had been repeatedly painted with Indian-ink. Exposed in blackened box at 8° 30' before S.W window— Bright day

Oct 2d 4° 30' P.m All with white glass-tubes as much bent as any

In this pot — 3 black quite vertical — 3 slightly inclined to light & in 2 of these there were cracks in black paint

At 5° P m. the 3 vertical ones had blackened pipes taken— off & exposed to lamp at 10° Pm well curved tight, except the one which had got smeared with gum & lamp-black, & this only slightly curved— (N.B only 1 pipe thus painted.)

Second Pot—9° a.m older seedlings & not so straight with 4 3 blackened & 4 3 unblackened tubes, exposed & treated in same way.—

Oct 2d 4° 30' the 3 blackened ones all inclined to light, but in all these 3 there were distinct small crack & blemishes through which light entered. (We have mentioned evidence of bands in part not illuminated beneath ground.—

{Perhaps most striking evidence of the regulating power was tubes with little windows — (This sh What is advantage?

We must conclude from all facts now given that illumination of upper parts determines bending of lower part; yet I think — lower part requires a certain amt of Paint.

[92]

Oct 3d 1878

Phalaris Light — Glass Pipes

glass-pipes blackened all— other arrangements like yesterday about 1/2 or rather less than length of cotyledons.

4° 45 Pm

Pot I. one black-pipe with green— as much curved as any, but then pipe not 1/3 of length of Cot (do not count)

Pot (2.) very slightly curved to Light— pipe not half length— pipe impervious to light

(3) (4) vertical Both

(5) very slightly curved at nearly right angles to light, & on one side the proper side a plain crack when held up to light & viewed through light in the black varnish

(do not count)

Pot. 2. (6) — slightly curved to light, but basal part not nearly so much curved as in all other seedlings

(7) vertical

(8) do

(9) moderately curved, except basal part

(10) considerably curved, except basal part & this only a trace

(11) very slightly curved basal part quite upright

(12) just a trace of curvature— but not basal part

In all these 12 10 specimens, there is the most conspicuous difference between the basal part, & that of all the scores of specimens without pipes

Rapid growth lifts up pipes.

Oct 4th next morning the same ones had straightened themselves through apogeotropism (5° 25 caps taken off & put before Lamp. — 10° 15. Pot I 3 greatly curved to light— one slightly blackened hardly at all curved. Pot 2. 4 greatly curved; 2 only slightly curved (& one of these much blackened & probably injured.)