SUMMARY 



l8 3 



after the determination of the photosynthesis under the 

 different rays. It should be remembered that the determina- 

 tion of the energy of the different rays was made upon the 

 spectrum given by the carbon disulphide prism at a particular 

 season of the year, from January to March. The following 

 results for the 16th and 19th January are seen to be 

 practically the same. 



Table XXV. — Showing the Distribution of Energy in the 

 Spectrum produced by the CS 2 Prism 



Radiation was detected at some considerable distance 

 beyond the extreme red. At about 850 /a/a the mean 

 deflection of the Radiometer was 85 divisions ; at 790 /a/a 

 the energy was found to be 147, which was the maximum. 

 At A (760 /i/i) the deflection declined to 145 ; at a (720 /a/a) 

 it was reduced to 132 ; C (656 /a/a) gave a deflection of 97. 

 At the sodium line D (590 /a/a) 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. 



Summary 



A pure spectrum of high dispersion was obtained by the 

 employment of a CS 2 prism. Arrangements were made such 



