MAXWELL, James Clerk (1831-1879). "On a Method of Making a Direct Comparison of Electrostatic with Electro-magnetic Force; with a Note on the Electromagnetic Theory of Light". In Proceedings of The Royal Society, Vol. XVI, No. 103, June, 1868. 8o (217 x 140 mm). Original printed green wrappers. -- [With:] Proceedings of The Royal Society, Vol. XVI, Nos. 94-104, June 1867-June 1868. 8o (215 x 138 mm). Original printed green wrappers (losses to a couple of front wrappers, spines chipped, very slight soiling to extremities). -- [With:] MAXWELL, James Clerk. An Elementary Treatise on Electricity. Oxford: Clarendon Press, 1881. 8o (214 x 138 mm). Text diagrams, 6 lithographed plates. Original terracotta cloth (slight wear to joints and extremities). Provenance: Atherton H. Sprague (signature on front pastedown). FIRST EDITION. Published posthumously, and comprising the text of a portion of his lectures given on electricity at the Cavendish Laboratory. (12)