256 Capt. W. de W. Abney and Mr. G. S. Edwards. 



Table IV. 



Ag 3 Br.Cl. (Gelatine plate.) See Fig. 4. 



Scale 

 number. 



Mean 





Relative 



Reduced 

 to maxi- 

 mum 

 of 100. 



Ordinate 

 of curve 



Scale. 



sector 

 reading. 



Opacity. 



sensi- 

 tiveness. 



to wave- 

 length 

 scale. 



Exposure. 



Sector 

 reading. 



Bare 













mins. 





glass 



72 















9 



71 



1 



28 



23 



23 



5 



17 



10 



63 



9 



49 



41 



41 



4 



25 



10i 





28 



84 



70 



70 



3 



41 



11 



29 



43 



112 



94 



94 



2 



57 



m 



25 



47 



120 



100 



100 



H 



65 



12 



29 



43 



112 



94 



95 



1 



71 



12^ 



30 



42 



110 



91 



91 







13 



37 



35 



97 



81 



81 







13| 



47 



25 



79 



66 



66 







14 



58 



14 



58 



48 



48 







14| 



68 



4 



38 



32 



32 







15 



71 



1 



28 



23 



23 







