The next year, 1861, is of great importance in the history of electrical science. The British Association met at Manchester, and a Committee was appointed on Standards of Electrical Resistance. Maxwell was not a member. The committee reported at the Cambridge meeting in 1862, and were reappointed with extended duties. Maxwell’s name, among others, was added, and he took a prominent part in the deliberations of the committee, which, as their Report[30] presented in 1863 states, came to the opinion, “after mature consideration, that the system of so-called absolute electrical units, based on purely mechanical measurements, is not only the best system yet proposed, but is the only one consistent with our present knowledge both of the relations existing between the various electrical phenomena and of the connection between these and the fundamental measurements of time, space, and mass.” Appendix C of this Report, “On the Elementary Relations between Electrical Measurements,” bears the names of Clerk Maxwell and Fleeming Jenkin, and is the foundation of everything that has been done in the way of absolute electrical measurement since that date; while Appendix D gives an account by the same two workers of the experiments on the absolute unit of electrical resistance made in the laboratory of King’s College by Maxwell, Fleeming Jenkin, and Balfour Stewart. Further experiments are described in the report for 1864. The work thus begun was consummated during the year 1894 by the legalisation throughout the civilised world of a system of electrical units based on those described in these reports. Meanwhile, Maxwell’s views on electro-magnetic theory were quietly developing. Papers on “Physical Lines of Force,” which appeared in the _Philosophical Magazine_ during 1861 and 1862, contain the germs of his theory--expressed at that time, it is true, in a somewhat material form. In the paper published January, 1862, the now well-known relation between the ratio of the electric units and the velocity of light was established, and his correspondence with Fleeming Jenkin and C. J. Munro about this time relates in part to the experimental verification of this relation. His experiments on this matter were published in the “Philosophical Transactions” for 1868. This electrical theory occupied his mind mainly during 1863 and 1864. In September of the latter year he writes[31] from Glenlair to C. Hockin, who had taken Balfour Stewart’s place during the second series of experiments on the measurement of resistance. “I have been doing several electrical problems. I have got a theory of ‘electric absorption,’ _i.e._, residual charge, etc., and I very much want determinations of the specific induction, electric resistance, and absorption of good dielectrics, such as glass, shell-lac, gutta-percha, ebonite, sulphur, etc.