348 D. Trowbridge on the Nebular Hypothesis. 
which separated as we have just supposed, a binary star wou ul 
be produced ;° and where there were three, a ternary system 
ould be found to exist in clusters, and that these pings are 
but parts of a cluster of clusters, and so on, each forming, as : 
were, an island universe. 1 the suns that make up thes 
clusters must be in motion,’ each nataeice its own individual 
course, while, at the samestime, it will be carried onward in its 
greater orbit ‘around the centre of gravity of the cluster e which 
it forms a part, and so on to the great centre of the w 
far as observation as yet enables us to judge, it is saath” that 
the stars wre arranged in clusters, but how nearly the grander 
conception, that the clusters are themselves arranged into sys 
tems, is true, we cannot at present decide 
10. As each sun forms the centre of a a planetary system (in 
all probability), there must have been as many centre s of con- 
densation as there are suns, or fixed (?) stars as in common /an- 
guage we call hess 
11. Now, although we have been unable to tell just how 4 
motion of rotation commenced, et we have shown what condi- 
tions must be fulfilled in order for she: matter to condense into 4 
sphere without generating a rotatory motion; and as those con- 
* If several centres of condensation pop. as we apie supposed, and any one 
of them should separate from the others, it would seem to be more Tikely that the 
d portio = ie ean tes cise that would « cause it ae rotate in the op- 
peer 
Le os aes vol. xxxvii, 1864, p. 233. where Prof. Kirkwood cies ted 
for the great eccentricity of the orbits of double stars, as compa : 
ets. 
, ‘the suns of the universe have been formed by an h process @ as I 
___ have described in the text or not, since they exist, the Tera ae Mecharies toate 
_ pong cppahersgpoer sew tee the telescope detects te clust ead 
‘same p teach t the clusters must, be in motion. motions are 
di 5 ealtchat a 
