Mechanical Energy.' To these we may add his complete theory of Diamagnetic Action, his investigations relative to the Secular Cooling of our Globe, and the influence of internal heat upon the temperature of its surface." Sir David Brewster, after referring to other works, added that "the important conclusions which he obtained from 'The Theory of Induction in Submarine Telegraphy,' have found a valuable practical application in the patent instrument for reading and receiving messages, which he so successfully employed in the submarine cable across the Atlantic; and when that great work is completed, his name will be associated with the noblest gift that science ever offered to civilisation. By his delicate electrometer, his electric spark recorder, and his marine and land relation galvanometer, he has provided the world of thought with the finest instruments of observation and research, and the world of action with the means of carrying the messages of commerce and civilisation which have yet to cross the uncabled oceans that separate the families of the earth." In 1866, after the Atlantic Telegraph Cable had been successfully laid, Sir William Thomson received the honour of knighthood from the Crown. On the same occasion he was presented with the freedom of his adopted city--Glasgow. The degree of LL.D. was conferred on him successively by Trinity College, Dublin, by Cambridge and by Edinburgh Universities, and that of D.C.L. by Oxford. He is a Fellow of the London Royal Society, as well as that of Edinburgh; and he is an honorary and corresponding member of several learned societies abroad. On the loss of H.M.S. _Captain_, a Commission was appointed to investigate the merits of designs for ships of war. Of that Commission Sir William Thomson is a valuable and valued member, from his intimate acquaintance with dynamical science and the theory of stability. Sir William also conducts the operations of two committees appointed by the British Association to investigate the subject of Tides and Underground Temperature, the results of which are expected to settle many points of physical theory. The circumstances of Sir William Thomson's election to the presidential chair of the British Association for the Advancement of Science, and the remarkably able address which he delivered in opening the late Edinburgh meeting, are of such recent occurrence that they need not be recapitulated. Sir William Thomson married, in 1852, a daughter of the late Walter Crum, Esq., F.R.S., who has predeceased him. He is a Liberal in politics, and no one has taken a more active part than he in forwarding the interests of the Liberal candidates for the representation of the Universities. PRINCIPAL BARCLAY.