20 Herman Schultz, 



Sub-Classification of Regular Nebulae 



(Sir John HerscheTs Class I). 



Sub-Classes j 



in \ Magnitude 

 Respect of 



Brightness 



Roundness 



Condensation 



Resolubility 



1 



Extremely 

 or 



Very Large 



Extremely 

 or 



Very Bright 



Nearly 

 Circular 



Nuclear 



Resolved 



2 



Large or 

 Considerably 

 Large 



Bright or 

 Considerably 

 Bright 



Irregularly 

 Round 



With a Strong 



Central 

 Condensation 



Partially 

 Resolved 



3 



Pretty Large 



Pretty Bright 



Oval 



With a Fainter 

 or aFaintCentr. 

 Condensation 



Resoluble 



4 



Pretty or 

 Considerably 

 Small, or Small 



Pretty or 

 Considerably 

 Faint, or Faiut 



Elongated 



Missing a 

 Central 

 Condensation 



Granulate 

 or Spotted 



5 



Very or 

 Extremely 

 Small 



Very or 

 Extremely 

 Faint 



Much 

 Elongated 



Annular 



Milky 





For the understanding of this scheme the few following- elucidative remarks 

 on its respective columns will probably be sufficient. 



Magnitude (col. 1). 



1 >4<; 2 3 Vto2 "' 4 >V 3 ' ; 5 < V.'- 



In the case of "much elongated" nebulae the magnitude is not indicated. 



Brightness (col. 2). 



1 only a few of the brightest nebulae of Sir William Herschel's 



Class I, and Class VI. 



2 the brighter nebulae Class I. 



3 the middlebright and fainter nebulae Class I and the brightest Class II. 



4 the faintest nebulae Class II. 



5 Class ffl. 



So tar as an immediate comparison of the brightness of nebulae with that 

 of the stars is possible, I assume the nebulae of the 1 st class of brightness 



