[59]

June 17. 1879 Ipomœa (Pharbitis) cærulea & purpurea exposed to N.E Window on day rather bright, but sometimes cloudy — rest of room dark darkened— muslin blind up— Light acted strongly on Hypocotyl of some young seedlings.— Did not draw the stems to light — Plants about a foot in height; some rather taller & some shorter

name & Pot     Pot I I. cærulea     Pot II     Pot III do young Plant This started late in day I. purpurea IV   V       VI   VII     12)

Semicircle moving from light   minutes 70 84 68 72 78 76 82 72 49 78 10)729 81 87 72 75 58 62 85 85 69 73 66 76 12) 889 average 74.1 5 729 [+] 889 [=] 1618 [÷] 22 aver 73.5 minutes

Semicircle moving To light     52 75 95 66 77 74 62 104 81 85 771 52 70 66 79 78 81 68 76 84 63 72 67 12) 856 71.7 5 771 [+] 856 [=] 1627 [÷] 22) 73.95

Observations begun at 6° 45' am & finished at about 2° P.m.   Probable error hardly as much as 5m. (Although the stems are thus not in the least Heliotropic— the Hypocotyls of young seedlings of Ipomoea cærulea are very strongly Heliotropic, bending in few hours at right angles towards light— good case gradation towards Ivy.)   average 72.9 — 77.1               Extreme fluctuations in rate in same plant & different plants— In moving from light varied between 87m — in moving to light varied from 104 to 52 m.m.— The first semicircle was quicker to light than from it in 6 out of 7 cases

It is evident travel at same average rate 2 & from light.

[60]

June 17th 1879 Ipomœa cærulea — N.E— window

Moderately bright day High-Cloud— Changeable Room darkened, except 1 window

[sketch] Hypocotyls strong Heliotropic

(1) 6° 45 facing to light — (Young Plant)
  7° 55' about from light moving from light 70m
  8° 47' tip to light ── to ── 52
  10 11' from light ── from ── 84m
  11. 26' to light ── to ── 75m
  12. 34' to light ── from ── 68m
  2° 9' to light ── to    95m

(2) 6° 45' to light
  7° 57 from light moving from light 72m
  9° 3' to light ── to ── 66m.
  10. 21 from light ── from ── 78m
  11. 38' to light ── to ── 77
  12. 54' from light ── from ── 76
  2°. 8' to light ── to ── 74

(3) 6° 45 to light
  8° . 7' from light moving from ── 82 m.
  9° 9' to light ── to ── 62m.
  10. 21 from light ── from ── 72
  12. 5' to light ── to ── 104
  12. 54 from light ── from ── 49m
  2°. 15' to light ── to ── 81

[60]

[Proof sheet of Forms of flowers, published pp. 88-9.]

[61]

June 17th 1879 Ipomoea purpurea N.E. window

(4)
6° 45' facing to light ──  
  8. 6 from light ──  from 81m.
  8' .58' to light ──   to 52m.
  9. 8' 10° 25 from light ──   from 87m
  11°. 35' to light from to . 70m
  12. 34 from light
  12. 47' from light ──   from 72m
  1°. 53' to light ──   to 66m.
 

(5)
6° 45. to light
  8° from light ── moving from ── 75m
  9° 19' to light ── to ── 79m
  10. 17' from light from ── 58m
  11. 45 to light ── to ── 78
12. 47' from light ── from ── 62m
  2° 6' to light ── to ── 81
6

(6)
6 45 to light   8°. 10' from light — moving from 85m    43 [-] 18 [=] 25
  9° 18' to light ── to ── 68m.
  10 43' from light from ── 85
  11. 59' to light ── to ── 76
  1° 8' from light ── from ── 69m
  2. 32' to light ── to ── 84'
  3 50. from light

(7)
6° 45 facing to light
  7 58 from light ── moving from ── 73m
  9° 1' to light ── to ── 63m.
  10. 7' from light ── from ── 66m
  11° 19' to light ── to ── 72
  12 35 from light ── from ── 76
  1° 42' to light ── to    76m.

[61v]

[Proof sheet of Forms of flowers, published pp. 87-8.]

[62]

First in moving

Moving from light

70 [+] 72 [+] 82 [+] 81 [+] 75 [+] 85 [+] 73 [=] 5380 [÷] 7 [=] 76.8

Moving to light

52 [+] 66 [+] 62 [+] 52 [+] 79 [+] 68 [+] 63 [=] 4420 [÷] 7 [=] 63.1