1872.] ' The Construction of the Heavens. 319 
that he regarded the nebule in two aspects at this time. 
‘There were some which he held to be parts of a much larger 
nebula, possibly parts of our own Milky Way. Others he 
held to be external Milky Ways, and therefore themselves 
made up of subordinate nebule. At this stage of his career, 
however, he seems to have entertained no doubt as to the 
stellar characterof any nebule ; and it is to the ideas he thus 
early promulgated respecting the nebule, that we must 
ascribe the common but altogether erroneous opinion, that 
Herschel regarded all the nebule as external galaxies of 
suns. He never entertained so general a theory as this; but 
even the theory he did entertain in 1785 respecting some of 
the nebulz was modified ere long as respects a very large 
proportion of those objects. 
He had not changed his views, however, in 1789, when he 
compared the nebulz of various orders to plants in various 
stages of growth. The following passage does not relate, as 
has been asserted, to his hypothesis of the development of 
nebulz into stars, but relates to various orders of stellar 
systems. ‘‘ This method of viewing the heavens,” he says, 
referring to the view that differences of antiquity may 
account for the different appearances of nebule, ‘‘ seems to 
throw them into a new kind of light. They now are seen to 
resemble a luxuriant garden, which contains the greatest 
variety of productions in different flowering beds; and one 
advantage we may at least reap from it is, that we can, as it 
were, extend the range of our experience to an immense 
duration. For to continue the simile I have borrowed from 
the vegetable kingdom, is it not almost the same thing 
whether we live to witness successively the germination, 
blooming, foliage, fecundity, fading, withering, and corrup- 
tion of a plant, or whether a vast number of specimens, 
selected from every stage through which the whole plant 
passes in the course of its existence be brought at once to 
our view. 
Butthe time was approaching when Herschel was to form 
entirely new views respecting the constitution of the heavens. 
I pass over the paper of 1796—though if space permitted I 
might quote passages from it, suggesting in a very interest- 
ing manner the progression of Herschel’s ideas—and turn to 
the paper of 1802. There can be no mistaking the import 
of the following passages from this important paper :—‘‘ The 
stars we consider as insulated,” says Herschel, ‘‘ are also 
surrounded by a magnificent collection of innumerable stars, 
called the Milky Way, which must occasion a very powerful 
balance of opposite attractions, to hold the intermediate 
