MacDonald, John. A Treatise on Telegraphic Communication, Naval, Military, and Political: in which the known Defects of the Present System of Telegraphic Practice by Sea and Land are obviated by the Introduction of a Numerical Portable Dictionary... IV, 186 pp. 5 (1 kolor.) Tables by S. Neele. 21 x 13 cm. New semi-leather (good condition) with gold plating. London, Military Library, 1808. Not in Ronald's Libr. See Poggendorff II, 5. – "Lieutenant-Colonel John Macdonald (1759-1831), F.R.S., who was already known by two Reports on the Diurnal Variation ... publishes two treatises upon his 'Terrestrial Telegraph' ... His contrivance consists of thirteen boards or shutters arranged, like those of Edelcrantz, into three verticalranks representing dogs, tens and units. Twelve of the boards are capable of producing 4095 distinct combinations, and the thirteenth or auxiliary board, which is mounted over the centre of the apparatus, doubles that number. A flag or vane is added to the dogred side to distinguish it in whatever direction it may be viewed, and a ball sliding upon the staff which supports it attachments the means of again doubling the number, so that, on the whole, 16,380 distinct signals can be obtained." (Mottelay p. 399). Macdonald served for a long time at the East India Company, before returning to England in 1800 and, in addition to his military service, devoted himself mainly to questions of earth magnetism. – Lightly tanned, 2 sheets with an old restored tear.