$12 Dr. Herschel's Astronomical Observations 
denote that perhaps some of the nebulous matter still re- 
maining in the branches, before it subsides into the nucleus, 
begins to take a spherical form, and thus assumes the sem- 
blance of a faint chevelure surrounding it in a concentric 
arrangement? And, if we may venture to extend these queries 
a little farther— will not the matter of these branches in their 
gradual fall towards the nucleus, when discharging their sub- 
stance into the chevelure, produce a kind of vortex or rotatory 
motion ? Must not such an effect take place, unless we suppose, 
contrary to observation, that one branch is exactly like the 
other ; that both are exactly in a line passing through the 
center of the nucleus, by way of causing exactly an equal 
stream of it from each branch to enter the chevelure at op- 
posite sides ; and, this not being probable, do we not see some 
natural cause which may give a rotatory motion to a celestial 
body in its very formation ? 
27. Of round Nebula that shew the Progression of Condensation, 
When round nebulae have a nucleus, it is an indication that 
they have already undergone a high degree of condensation. 
From their figure we are assured that the form of the nebu- 
losity of which they are composed is now spherical, whatever 
may have been its original shape ; and being surrounded by 
a chevelure, we may look upon its different evanescent degrees 
of faintness as a sign whereby to judge of the gradual pro- 
gress of the consolidation of the nucleus. The following 
seventeen nebulae are given in two assortments.* 
* See fifteen round or nearly round nebulae, with a nucleus and faint chevelure . 
I. 40, 137, 226, 242, 251, 262. II. 321. 111 . 291, 373. IV. 23, 54, 56, 59, 76. 
Connoiss. 32. 
Two nebulceivitb a nucleus and chevelure resembling nebulous stars. II. 3a. III. 99. 
