216 
ASTRONOMY. 
from eternity. This consequence arises out of the hypoth¬ 
esis with still more certainty, if we make a part of it, what 
the philosophers who mantain it have usually taught, that 
the planets were originally masses of matter, struck off in 
a state of fusion from the body of the sun by the percus¬ 
sion of a comet, or by a shock from some other cause, with 
which we are not acquainted: for, if these masses, partak¬ 
ing of the nature and substance of the sun’s body, have in 
process of time lost their heat, that body itself, in time 
likewise, no matter in how much longer time, must lose its 
heat also, and therefore be incapable of an eternal dura¬ 
tion in the state in which we see it, either for the time to 
come, or the time past. 
The preference of the present to any other mode of dis¬ 
tributing luminous and opaque bodies, I take to be evident. 
It requires more astronomy than I am able to lay before 
the reader, to show, in its particulars, what would be the 
effect to the system, of a dark body at the centre, and of 
one of the planets being luminous; but I think it manifest, 
without either plates or calculation, first, that supposing 
the necessary proportion of magnitude between the central 
and the revolving bodies to be preserved, the ignited planet 
would not be sufficient to illuminate and warm the rest of 
the system; secondly, that its light and heat would be im¬ 
parted to the other planets much more irregularly than 
light and heat are now received from the sun. 
( # ) II. Another thing, in which a choice appears to be 
exercised, and in which, amongst the possibilities out of 
which the choice was to be made, the number of those 
which were wrong bore an infinite proportion to the num¬ 
ber of those which were right, is in what geometricians 
call the axis of rotation. This matter I will endeavour 
to explain. The earth, it is well known, is not an exact 
globe, but an oblate spheroid, something like an orange. 
Now the axes of rotation, or the diameters upon which such 
a body may be made to turn round, are as many-as can be 
drawn through its centre to opposite points upon its whole 
surface: but of these axes none are permanent , except 
either its shortest diameter, i. e. that which passes through 
the heart of the orange from the place where the stalk is 
inserted into it, and which is but one; or its longest diame¬ 
ters, at right angles with the former, which must all ter¬ 
minate in the single circumference which goes round the 
thickest part of the orange. The shortest diameter is 
that upon which in fact the earth turns; and it is, as the 
reader sees, what it ought to be, a permanent axis; where- 
