^* The Laplace transform is reserved for Vol. IV, but the reference to Heaviside'e operational method on p. 108 is somewhat misleading, since it can be read as implying that there is no difference between the Heaviside method and the D method sc familiar in English textbooks, a method much older than Heaviside, even older than Boole, to whom so much of its development and of its currency in English texts ir due. A definitive account of the history of these processes is given by Cooper, J.L.B, Gazette, 36, 6–19.Google Scholar