XX 



ILLUSTRATIONS 



FIG. PAGE 



28. Curve showing variation of photosynthetic efficiency at various 



rates of intermission of light . . . . 96 



29. The Self-Recording Radiograph ...... 101 



30. Radiogram of variation of intensity of light from the sky during 



twelve hours in winter . . . . . 104 



31. Record of diurnal variation of light and of temperature in 



summer ......... 105 



32. The Portable Electric Photometer . . . ... 109 



33. The photosynthetic curve under variation of C0 2 - concentration 115 



34. Curve of photosynthesis of Elodea under variation of C0 2 -con- 



centration (after Blackman) . . . . . .117 



35. Electric response of Cicer avietinum . . ... 125 



36. Photosynthetic curves under increasing concentration of CO a 



and of malic acid solution . . . . . . . 129 



37. The Plant-vessel with Bubbler for variation of temperature . 135 



38. Responses of Mimosa to testing stimulus of same intensity 



through cyclic variation of temperature . . 139 



39. Photosynthetic curve under variation of temperature . .140 



40. Curve of growth under variation of temperature . . . 140 



41. Negative hysteresis . . . . . . . .151 



42. Positive hysteresis . . . . . . 151 



43. The complete apparatus : Bubbler, Photometer and Thermo- 



graph 158 



44. Automatic records of successive Bubblings for five minutes 



during different periods of day . . . . . . 160 



45. The curves for light, temperature and photosynthetic activity . 163 



46. Record of photosynthetic activity under different coloured 



light by Method of Flotation . . . . . 168 



47. Records of response under sunlight, red light and blue light . 171 



48. Arrangement for obtaining pure solar spectrum . 177 



49. The Magnetic Radiometer ....... 180 



50. Heterostatic method for rendering ineffective stimulus effective 189 



51. Curves showing distribution of energy in the spectrum and 



corresponding photosynthesis ...... 193 



52. The Torsion Balance for measurement of increase of weight of 



living plant during photosynthesis . . . . 206 



53. Chemical Balance for determination of increase of weight of 



Hydrilla after exposure to light . . . . .213 



54. Eudiometer for collection of oxygen evolved under light . . 214 



55. Apparatus for determination of efficiency of photosynthetic 



organ .......... 229 



56. Curve showing the change of volume of 1 grm. of water at 



different temperatures ........ 241 



57. The physiological zero in photosynthetic curve for variation of 



temperature ......... 244 



58. Photosynthetic curve for variation of C0 2 -concentration and the 



physiological zero . . . . . . . . 247 



59. Photosynthetic curve with physiological zero for variation of 



intensity of light ........ 248 



60. Photosynthetic curves for variation of temperature carried 



through a cycle for two intensities of sunlight . . . 260 



