NEBULiB. m

ef the Catalogue of 1833) have a photosphere, whoso diam-
eter measures from 2' to 3'.*

The large nebulous masses of irregular configuration com-
pose a class of nebulae diflering entirely from those we have
described as regular, and which are, at all events, faintly de-
fined. They are characterized by the most variously unsym-
metrical forms, having indefinite and confused outlines. These
bodies, which constitute mysterious phenomena std generis,
have mainly given occasion to the opinions advanced in ref
erence to the existence of cosmical clouds and self-luminous
nebulce, supposed to be distributed through the regions of
space, and to resemble the substratum of the zodiacal light.
