[ 547 ] 
L. A Supplement to a former Paper^ 
concerning Difficulties in the Newtonian 
Theorjr of_ Light : hy the Rev, S. Horfley^ 
L L. B, F, R, S. 
Problem I. 
Read Dec. 1,9, ^ P ARCKL of equal Circles being dlf-' 
/L pojed upon a plane Jurface, of any 
figure whatfioever, in the clofiejt arrangement po[]ihle^ 
to determirw the ultimate proportion of the fpace covered 
by all the Circles^ to the fpace occupied by all their 
InterficeSy when each circle is inpnitely fmally and 
the fpace y over which they are difpofedy is of a. fake 
magnitude. 
The clofeft manner, in whiclr a parcel of equal' 
circles can be difpofed upon a plane, is when the 
centers of every three contiguous circles are htuated’ 
at the angles of an equilateral triangle, which hath 
* each of its fides equal to a diameter of any one 
of the circles. 
A number of circles, thus difpofed', may be di- 
vided, as Tab^ XVII. lliews,. into feveral. rowTS 
of circles, having their centers ranged upon parallel 
right lines, AG, IIP, Q.X, r 'Zi 6cc. Every, 
4 ^ 2 .circle,. 
