THE ENERGETICS OF PHOTOSYNTHESIS 



41 



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Fig. 20. Early experimental equipment devised by Warburg. Hg: mercury lamp, b, 

 Ji, J'>: diaphragms. Z-i, L^: lenses. F: cuvettes filled with colored solutions. .S'2.- 

 mirror {S\: position of the mirror for light intensity measurement). B: bolometer with 

 Wheatstone bridge. T: manometer vessel. M: manometer. A'.- cathetometer. 



" s a a 



Fig. 21. Newer experimental equipment in Prof. Warburg's institute. For the sake of clarity 



the thermostat is not shown. 



is connected to the manometer and moves synchronously with it in the 

 horizontal plane (see Fig. 22). The cross-section of the beam of light is no 

 longer round but has the same shape and surface area as the bottom of the 

 manometer vessel. This provides almost complete illumination of the cell 

 suspension. After removal of the manometer vessels, the beam of light is 

 reflected by the mirror Afg into the horizontal plane and, with the aid of a 



