252 The Construction of the Heavens. (July, 
perfectly symmetrical, so there may be some place in the 
universe where the arrangement and motions of the stars 
may appear most beautiful. If we suppose the sun to 
be plunged in a vast stratum of stars of inconsiderable 
thickness compared with its dimensions in other respects, it 
is not difficult to see that the actual appearance of the 
heavens may be reconciled with a harmonious arrangement 
of the constituent bodies of such a system with respect 
to some common centre, provided it be admitted at the 
same time that the stars have all a proper motion. In 
such a system it is manifest that the distribution of the 
stars would appear more irregular the farther the place 
of the spectator was removed from the centre of the 
stratum towards either of the sides. It is also evident that 
the stars would appear to be distributed in least abundance 
in the opposite directions of the thickness of the stratum, 
the visual line being shortest in those direCtions; and that 
the number of visible stars would increase as the stratum 
was viewed through a greater depth, until at length, from 
the continual crowding of the stars behind each other, 
it would ultimately assume the appearance of a zone of 
light.’* 
It will be obvious that we have here a complete enuncia- 
tion of what has been called the Grindstone theory of the 
stellar system. The theory is based by Wright on observed 
facts, precisely as it was afterwards based by Sir W. 
Herschel on other observed faéts. Assuredly whatever 
credit appertains to the invention of the theory must be 
in justice ascribed to Wright, who thus in 1750 reasoned 
out and clearly described the views to which Herschel was 
led in 1784. Wright, indeed, did not convince his contem- 
poraries. Either they were unwilling to examine the 
reasoning he advanced, or they could not recognise its 
force ; but neither remissness nor slowness of apprehension 
on their part can afford just ground for depriving Wright of 
the credit due to his ingenious analysis of known facts. 
Kant’s speculations, so far as they relate to the present 
constitution of the universe, must be regarded as simply an 
extension of Wright’s theories. Kant had read Wright’s 
work, the ‘‘ Theory of the Universe,” which had been 
reprinted in a Hamburg journal of the year 1751, and 
he admits that his views respecting the universe of stars 
were suggested by Wright’s theories; but he found himself 
* T have not followed here Wright’s actual text, not having present access 
to his work. The above passage is taken from the abstract of Wright’s theory 
in Professor Grant’s excellent ‘‘ History of Physical Astronomy.” 
