Copy letter from Arthur William Rucker, to Joseph Ernest Petavel, [Fellow of the Royal Society], 34 Abingdon Mansions, Kensington, W. Petavel's paper, 'An Experimental Research on some Standards of Light' subject to Petavel's compliance with the stated suggestions as to figures [is accepted for publication]. It is suggested that the illustrations, except the photographs, should be reproduced on a small scale. The photographs are more puzzling than a good diagram. 3 November 1899