270 



CAPTAIN \V. UK \V. Al'.NKV <>\ T11K 



(XX.) Sub-division of Luminosity into Sensations. 



Having ascertained the percentage composition in sensation luminosity of all the 

 spectrum, the luminosity curve of any known spectrum can be sub-divided into 



Fig. 3. 



\ 



\ 



a * ii a a u a a M w a 11 a n x 



> to t> u u n a st 



Percentage of colour sensations as luminosity in the prismatic spectrum colours. 



Fig. 4. 



-t I * a 10 I? H . '8 ?r ; ?B JO 3( 54. 36 38 40 4? 4 50 V M 56 S8 60 6J M 



Sensation-luminosities in the spectrum of the light of the crater of the positive pole of the arc light as 



. seen with the centre of the retina. 



| 



sensation-luminosities. This is done in the next table. Columns X., XL, XII., 

 XIII. , XIV., XV. and XVI. give the sensation-luminosity curves derived from the 

 total luminosity curve of the spectrum of the crater of the positive pole of the arc 



