* Magnitude from Hopmann.
† N.G.C. 524 and 3998 are late elliptical nebulae in which the
equatorial planes are perpendicular to the line of sight. They might be
included with the E6 or E7 nebulae.
§ Absorption very conspicuous.
‡ N.G.C. 3607, 4459, and 5485 appear to be elliptical nebulae with
narrow bands of absorption between the nuclei and the peripheries.
The progressive change in the value of C throughout the sequence may be
expressed as a variation either in the magnitude for a given diameter
or in the diameter for a given magnitude. Both effects are listed in
Table VII and are illustrated in Figure 6, in which magnitudes and
diameters thus found are plotted against types. With the exception of
the later elliptical nebulae, for which the data are wholly inadequate
for reliable determinations, the points fall on smooth curves. In the
region of the earlier elliptical nebulae, the curves should be somewhat
steeper in order to allow for objects of greater ellipticities which
are probably included.