Plate, figure 14 showing curve of caustic made of two circles by Arthur Cayley Figure 14 showing the curve of a caustic consisting of two circles, one within and one outside the reflecting circle. Subject: Mathematics Published in Philosophical Transactions as 'A memoir upon caustics'. Written by Cayley at 2 Stone Buildings [Lincoln's Inn, London]. Received by the Royal Society on 1 May 1856. Read 8 May 1856. [1856]