mv × v ⁄ r = mv2 ⁄ r.
[21] See Gray's Lehrbuch der Physik, s. 278. Vieweg u. Sohn, 1904.
[22] Gray, Royal Institution, Friday Evening Discourse, February 1898.
[23] See the Reports of the Committee on Electrical Standards, edited by Prof. Fleeming Jenkin, F.R.S., Maxwell's Electricity and Magnetism, and Gray's Theory and Practice of Absolute Measurements in Electricity and Magnetism, Vol. II, Part II.
[24] The writer once, on a thick night, in a passenger steamer in the Race of Alderney, when the engines were stopped and soundings were being taken, saw the reel and cord go overboard, nearly taking one of the men with it. A new hank of cord had to be got and bent on a new reel; an operation that took a long time, during which the exact locality of the ship was a matter of uncertainty. Comment is needless!
[25] The tuning of a major third, in this way, is described in the paper entitled "Beats on Imperfect Harmonies," published in Popular Lectures and Addresses, vol. ii.
[26] The writer well remembers meeting a man of some experience in cable work who was on his way to measure the alternating currents in a Jablochkoff candle installation by the aid of an Ayrton and Perry galvanometer with steel needle!