Photometry of Lights of Different Colours. 859 



iact that owing to differences in shape certain curves would 

 have less weight than others if plotted in terms of equal 

 maxima or equality at any arbitrarily chosen wave-length. 

 According to the results of the paper just previous in this 

 series, the one thing common to all the curves would be 

 their area when the comparison light and the light dispersed 

 into a spectrum were identical. 



The data of all observers are given in Table I., with their 

 mean. Table II. gives the mean values in terms of the 



Table I. 

 Normal Spectrum Luminosity Curves of Eighteen Observers. 



Observer. 



•481 



•498 



•518 



•537 



■556 



•576 



•595 



•615 



•635 



•655 n 



1. P.W.C. 



3-4 



' 59 



13-75 



17-4 



17-95 



174 



140 



955 



5-2 



1-7 



2. L.H.K. 



415 



7-1 



15-5 



18-7 



18-6 



16-5 



122 



75 



3-65 



115 



3. E.J.E. 



3-05 



5-9 



13-8 



1S-4 



18-95 



17-15 



13-35 



8-65 



385 



1-4 



4. W.M.M. 



3-6 



7-4 



15-2 



18-45 



1905 



16-65 



12-45 



7-75 



38 



115 



5. M.D.C. 



33 



655 



15-0 



19-3 



19-25 



17-6 



12-75 



7-65 



3-45 



1-35 



6. F.E.C. 



2-3 



505 



13-9 



17-9 



191 



17-55 



143 



9-4 



4-95 



1-95 



7. M.L.I. 



3-25 



5-45 



12-75 



17-8 



18-9 



17-8 



13 7 



9 05 



455 



1-9 



8. M.L. 



33 



7-7 



14-2 



187 



198 



18-2 



123 



73 



3-45 



1-35 



9. H.A.E, 



33 



6-9 



14-2 



17-7 



17'8 



172 



13-45 



9-0 



4-65 



200 



10. L.E.G. 



2-65 



695 



159 



19-55 



199 



17-2 



12-3 



7-7 



29 



09 



11. M.M. 



39 



7-2 



14-7 



1735 



18-5 



16-65 



1315 



8-05 



340 



1-2 



12. C.F.L. 



2-7 



5-45 



13-2 



18-1 



18-7 



17-5 



1415 



9-2 



4-9 



1-6 



13. A.J.S. 



255 



5-7 



15-2 



19 05 



19-5 



17-45 



13-5 



8-25 



41 



1-4 



14. A.W. 



1-6 



3-65 



12-65 



16-9 



18-05 



18-25 



15-6 



11-05 



5-85 



2-3 



15. H.H.M. 



2-6 



6-1 



14-85 



18-0 



19-45 



17-8 



1395 



8-4 



4-15 



1-3 



16. T.W.K. 



3-7 



74 



14-15 



19-9 



20-1 



17-5 



12-0 



67 



315 



1-25 



17. H.E.I. 



30 



6-1 



15-35 



18-75 



193 



17-4 



13-45 



8-25 



3-9 



1-5 



18. GhC. 



2-15 



5-2 



126 



18-8 



19-4 



17-1 



14-0 



9-3 



5-0 



1-6 



Mean 



3-03 



62 



14-55 



18-38 



1903 



17-47 



1336 







852 



4-16 



„ 







Table II. 





itive 



Luminous 



Efficiencies of Sp 



X. 







\. 



•44 fx 



•029^1 





'57 jx 



•45 



•047 | 







•58 



•46 



•073 







•59 



•47 



•107 J 







•60 



•48 



•154 







•61 



•49 



•235 







•62 



•50 



•363 







•63 



•51 



•596 







•64 



•52 



•794 







•65 



•53 



•912 







•66 



•54 



•977 







•67 



•55 



1-000 







•68 



•56 



•990 



* Extra 



polatei 



, 



948 



875 



763 



635 



509 



387 



272 



175 



104 



0681 



044 I 



026 J 



/ 



