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Dr. Herschel's Astronomical Observations 
length of time required for this purpose must, however, 
greatly depend upon the original situation of the stars exposed 
to the clustering power. 
12. Of Clusters vanously extended and compressed. 
The outlines of clusters of stars in rich parts of the heavens, 
and even of those that are insulated, are seldom sufficiently 
defined to arrange such clusters by their figure; and as the 
following assortment contains some that are variously ex- 
tended and differently compressed, it will be seen, from the 
descriptions of a few of them, that the power which has drawn 
the stars together must have acted under different circum- 
stances.'^ 
VI, 3 is “ A cluster of very compressed, extremely small 
% 
“ stars, containing a few large ones. It is of an extended 
“ figure, and, as it were, divided. 
In this cluster the observed partial division points out the 
cause of its being extended, which may be ascribed to a double 
seat of preponderating attractions at some little distance from 
each other. 
VI, 24 is “ A very rich cluster of extremely small and very 
“ compressed stars ; it is about & long and 4' broad.'" 
Here the stars of the cluster are not only much compressed, 
but the borders of it are moreover sufficiently determined to 
shew the limits of its extent; from which we may infer that 
the cluster is advancing towards insulation, and that in the 
end a gradual concentration may bring it to a globular form. 
* See fifteen extended clusters of stars; twelve in the milky way II, 198. VI, 3. 
14. 24. 36. VII, 18. 19. 27. 41. 44. 56. VIII, 3. And three near the milky way 
VII, 29. 64. VIII, 75. 
