Brightness of the Corona of January 22, 1898. 41 



Table I. — Comparison of Observed Brightness (Photographic) of 1898 

 Corona with the Law. 



Brightness x (distance from Sun's centre) 6 == constant. 



(The distances were measured in divisions of 13 to the Sun's radius. 

 The brightnesses are expressed by powers of 2, zero representing 

 Moon's brightness.) 



j Distance 

 1 from 

 ! Sun's 

 centre 

 in radii. 



Typical 

 brightness 

 of corona 

 alone. 



Typical 

 brightness 

 wit h 

 " glare " 

 added. 



Plate. 



01 



N. 



Dseived 

 I.E. 



error of formula. 

 E. S. S.W. 



w 



- 



1 -08 



- 



+ 01 



- 



+ 0-1 



I 



+ 0-6 



— 



-01 



+ 0-7 



— 



+ 0*4 



1 15 



- 0-4 



-0-4 



I 



+ 0-6 



-0 -1 



o-o 



+ 0-4 



-0-7 



+ 0-4 



1 -23 



- 1-0 



-1-0 



I 



+ 0-2 





-o-i 



+ 0-2 



-0-4 



o-o 



1 31 



— 1-5 



— 1'5 



I 



+ 0-5 



+ 0-1 



+ 0-2 



-0-2 



-0-3 



+ -1 



1 '38 



- 2-0 



-2-0 



I 



-0-4 





'0 



n -n 



\J u 





4-0-1 



1 -46 



- 2-5 



-2-4 



I 



o -o 



+ 0-1 



-0-5 



+ 0-3 



-o-i 



-o-i 



1 '61 



-3-3 



-3 -1 



I 



-0 3 



-0-5 



-0-7 



— 



o-o 





1 -77 



- 4-1 



-3 -8 



I 



— 



-01 



— 



— 



+ 0-2 



— 



1 92 



- 4-9 



-4-4 



I 



— 



-o-i 



— 



— 



+ 0-2 



— 



1 -31 



- 1-5 



-1*5 



II 



+ 0-3 



— 



— 



-o-i 



— 





1 -38 



— 2*0 



— 2 



II 



-o 







-0-3 



— 



+ *2 



146 



- 25 



-2 4 



II 



-0-2 



— 





-0-5 



— 



-o-i 



1 -54 



— 2 -9 



-2 8 



II 



-0-3 



+ 05 



+ 0-6 



-03 





-0-2 



1 -61 



- 3 3 



-3-1 



II 



-0 -4 



+ 0-1 



+ 0-2 



-0-3 



4-0-3 



-0-2 



1 '77 



- 4-1 



-3-8 



II 



-0'2 



-0-2 



+ 0-1 



— '1 



— 0*1 



-o-i 



1 -92 



- 4-9 



— 4-4 



II 



— 



-0-2 



+ 0-1 





+ 0-1 



■ 



2 -15 



-5-8 



-5-1 



II 



+ 0*1 



-0 -3 



+ 0-1 





4-0-2 





2 '54 



- 7-2 



-5-8 



11 



— 









+ 0-3 





1 -46 



- 2-5 



-2-4 



III 



o-o 







+ 0-1 







1-61 



- 3*3 



-3-1 



III 



o-o 







+ o-i 





o-o 



1 -77 



4*1 



— 3 -ft 



— o o 



III 



+ 01 



+ 0-4 



+ 0-2 



+ o-i 



o-o 



— U 1 



1 -92 



- 4-9 



-4-4 



III ' 



-o-i 



+ 0-2 



+ 0-2 



+ 0-1 



+ 0-1 



-0-2 



2-15 



- 5-8 



-5-1 



III 



-o-i 



o-o 



-0 -l 



+ 0-1 



o-o 



o-o 



2-54 



- 7'2 



-5-8 



III 



+ 0-2 



+ 0-2 



-f 1 



— 



o-o 



o-o 



2-92 



- 8-5 



-6-1 



III 





+ 0-4 



o-o 





-o-i 





1-92 



- 4-9 



-4-4 



IV 



+ o-i 







+ 0-3 







2 -08 



- 5-5 



-4-9 



IV 



+ 0-2 



-0-4 





+ 04 





4-0-4 



2 -23 



- 6-1 



-53 



IV 



-f 0-2 



-0 2 



o-o 



+ 0-4 





4-0-2 



2-38 



- 6 7 



-5 6 



IV 





-0.2 



+ o-i 









4-0-2 



2-54 



- 7-2 



-5-8 



IV 



+ 0-2 



-0-2 



o-o 



+ 0-5 



o-o 



4-0-2 



2-92 



- 8-5 



-6-1 



IV 



-o-i 



-0 2 



+ 0'1 



+ 0-3 



o-o 



+ 0-3 



3-31 



- 9-6 



-6-3 



IV 





-o-i +o-i 



+ 01 



-o-i 



o-o 



3-69 . 



-10 -5 



-8-3 



IV 





-0-2 



o-o 





-0-3 





4-08 



-11 -4 



-6-4 



IV 





-0-4 







-0-3 





15. Considering the irregularity of the coronal structure, we cannot 

 perhaps expect better agreement with any simple law of brightness 

 than is shown by these residuals ; and the assumed law, whether it has 



