Page:Collected Physical Papers.djvu/383

Rh Radiation was detected at some considerable distance beyond the extreme red. At about 850 μ μ the mean deflection of the Radiometer was found to be 85 divisions; at 790 μ μ the energy was found to be 147, which was the maximum. At A (760 μ μ) the deflection declined to 145; at a (720 μ μ) it was reduced to 132; C (656 μ μ) gave a deflection of 97. At the sodium line D (590 μ μ) the reading was 71; the energy of the spectrum underwent a further and continuous decline; at E, F, and G the deflections were 42, 27, and 10 respectively. (Physiology of Photosynthesis, 1925.)