356 Prof. J. Sebelien on the Distribution of Actinic Sunlight 

 where A = a 2 (a + la + ca 2 ), 



C = /3 2 (a + 3^+0m 2 ), 

 D=/3 3 (6 + 4ca), 



E = c/3 4 . 



Introducing in this expression various values of p we get 

 the values for the actinic direct sunlight, put in the column 

 W of Table II. 



The values for the diffused light, which we have put in 

 the column W x of Table II., we have calculated in a similar 

 way by means of the formula (2), where the quantities a, (3, 

 and f take the same values as in the calculation of the values 

 of W. 



The sum of W and Wj for each latitude is found in the 

 last column of the table, and shows the total amount of the 

 actinic light. 



Table II. 



Chemical Light-units pr. Unit Horizontal Area on 

 Midsu miner- da v. 





Direct 



Diffused 



Total light, 



N. lat. 



insolation, W. 



daylight, W,. 



W+W,. 





Light-units. 



Light-units. 



Light-units. 



0° 



60656 



22060 



82716 



10° 



70891 



23388 



94479 



20° 



77703 



24539 



102242 



30° 



89060 



25775 



114835 



40° 



79644 



27059 



106701 



45° 



76178 



27757 



103935 



50° 



72584 



28521 



101105 



55° 



62704 



28589 



91293 



60° 



62064 



30484 



92548 



65° 



57089 



32168 



89257 



66° 33'* 



54573 



33264 



87837 



70° 



50267 



35012 



85279 



75° 



44587 



37099 



SI 686 



80° 



40080 



38612 



78700 



90° 



36211 



39839 



76048 



* The northern polar circle. 



Fig. 1 gives a graphical representation of these numbers. 

 The lower dotted curve shows the variation of the diffused 

 daylight. We see that at the lower and middle latitudes 



