Plate XII.
Vol. II. page 328.
A Magic Circle of Circles
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Published as the Act directs, April 1, 1806, by Longman, Hurst, Rees & Orme, Paternoster Row.
There are, moreover, included four other sets of circular spaces, excentric with respect to the first, each of these sets containing five spaces. The centres of the circles that bound them, are at A, B, C, and D. Each set, for the more easy distinguishing them from the first, are drawn with a different coloured ink, red, blue, green, and yellow.[62]
These sets of excentric circular spaces intersect those of the concentric, and each other; and yet the numbers contained in each of the twenty excentric spaces, taken all around, make, with the central number, the same sum as those in each of the 8 concentric, viz. 360. The halves, also of those drawn from the centres A and C, taken above or below the double horizontal line, and of those drawn from centres B and D, taken to the right or left of the vertical line, do, with half the central number, make just 180.