380 



34 



Table 16. 



Integrated weight of //. 





plates from 



measured at 





number 

 of stars 



total weight 



fraction 



effective 

 wave- 



Mount Wilson 



Potsdam 



spectra of I order 



— - 11 — 



— - III — 



1156 

 57 

 92 



175116m-2 

 25828 

 44023 



■All 

 •070 

 •118 



lengtlis 





1169 



244967 



•659 





Copenhagen 

 Urania Obs. 



Copenhagen 

 University Obs. 





59 



42071 



•lis 





all effective wavelengths 



1169 



287038 



•772 



colour- 

 indices 



Göttingen and Harvard, vis. 

 Potsdam 

 Pulkovo 



19 



89 



234 



5700 

 41407 

 24879 



•015 

 •111 

 •067 





old colour indices 



241 



71986 



•194 



total content of the 10th column of the general catalogue 



1169 



359024 



•966 



Shapley and Richmond, new colour indices 



635 



12700 



•034 









grand total 



1176 



371724 



1^000 



ated. Thus the weights 4, 13, 22, 31 and 40 could accordingly be increased to 10, 

 20, 30, 40 and 50 respectively, but I have thought it safer to let them stand as 

 they are. 



The total weight of all the Ii values of the general catalogue is 371724 m~^. 

 This weight is distributed over the different series as indicated in Table 16. 



It is seen that the Mount Wilson effective ^vavelengths contribute 66 percent 

 of the total weight of /^ and all the effective wavelengths together 77 percent, while 

 the rest, 23 percent, is due to colour indices. 



As is seen in the general catalogue the weight of /^ is very different for 

 different stars. Thus for 76 stars the weight of Ix is greater than 1000 m~^. The 

 total weight for these 76 stars is 214716 m~- or 58 percent of the weight for all 

 the stars. 



18. The Map. 



The accompanying map of the Pleiades contained in the general catalogue 

 was drawn to the scale of 1 second of time equal to 1 millimeter. It has been re- 

 duced to Vio of the original size. The scale is about 1 mm to 45""9, the equivalent 

 focal length being 4494 mm. 



The diameters of the dots representing the single stars increase with the 

 apparent brightness of the stars in such a way, that a difference of 1 magnitude 

 corresponds to a difference in the logarithmus of the diameter of '06. This is 

 practically the same scale as used on the maps of the Bonner Durchmusterung. 



