5 
the Ring of Saturn. 
Inside diameter of the smallest ring 
5900 parts. 
Outside diameter - 
75 io 
Inside diameter of the largest ring 
7740 
Outside diameter - 
8300 
Breadth of the inner ring 
805 
Breadth of the outer ring 
280 
Breadth of the vacant space 
n 5 
Admitting, with M. de la Lande, that the breadth of the 
whole ring, as formerly supposed to consist of one entire mass, 
is near one third of the diameter of Saturn, it follows that the 
vacant space between the two rings, according to the above 
statement, amounts to near 2513 miles. 
In giving these proportions, which are merely taken from 
very accurate representations of the phsenomena that offered 
themselves, I do not mean to be scrupulously exact, but re- 
serve a greater accuracy for a future opportunity; when a 
micrometer, which I have lately applied to the 40-feet tele- 
scope, will assist me to have recourse to proper measures. 
It may be remarked, that this opening in the ring must be 
of considerable service to the planet, in reducing the space 
that is eclipsed by the shadow of the ring to a much smaller 
compass; both on account of the direct light it lets through, 
and because there will be a strong reverberation of the rays of 
the sun between the two opposite edges. Moreover, if these 
rings should be surrounded by some atmosphere, which is 
highly probable, the refractions that will take place upon the 
edges will still contribute to lessen the darkness which the 
shadow 7 of an undivided ring would have occasioned. 
As we have now admitted Saturn to have two rings en- 
tirely detached from each other, so as plainly to permit us to 
