Paper, 'On certain definite integrals. No 15' by W H L [William Henry Leighton] Russell Russell writes: 'Mr Fox Talbot’s researches on the comparison of transcendents are well known. The following are founded on the same principle, applied in a different manner:— a1x^3 + b1y^3 + c1z^3 = e1, a2x^3 + b2y^3 + c2z^3 = e2, be two equations connecting the variables x, y, and z.' Annotations in pencil and ink. Subject: Mathematics Received and read 16 June 1887. A version of this paper was published in volume 42 of the Proceedings of the Royal Society as 'On certain definite integrals. No. 15'. 1887