The physiology of photosynthesis / by Sir Jagadis Chunder Bose.

  • Bose, Jagadis Chandra, 1858-1937.
Date:
1924
Catalogue details

Licence: In copyright

Credit: The physiology of photosynthesis / by Sir Jagadis Chunder Bose. Source: Wellcome Collection.

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    THE AUTOMATIC RECORD OF THE RATE OF EVOLUTION OF OXYGEN The Automatic Recorder—Electric Pencil with double contact—The Electromagnetic Writer—Condenser for elimination of sparks— Recording Drum—The Governor for variation of speed within wide limits—-The Ink-Recorder—Maintenance of constancy of external conditions—Radiant point as a source of light—The experimental procedure—-Constancy of results—Advantages of the Automatic Method. In order to eliminate the error due to the personal equation, which necessarily attends the eye-observation of the Bubbler in action, it is essential to devise a method by which the periods of evolution of equal volumes of oxygen may be automatically recorded. This I have been able to secure by the following electromagnetic apparatus and accessories, which consist of: (1) A Pencil with double electric contacts which com- plete an electric circuit for each bubble. (2) An Electromagnetic Writer for inscription of the record of successive periods on smoked or white paper. (3) A Condenser for elimination of sparks at break of the circuit. (4) A Recording Drum. (5) A Governor by which the speed of the Drum may be adjusted within wide limits. The Electric Pencil.—The successive bubbles of oxygen move the oil-valve up and down through a short length. A drop of mercury is placed on the oil-valve, and the constriction at the end of the Bubbler is made so narrow that the mercury-drop always remains above the bend and does not sink into the oil forming the valve. The evolved