RARE early 20th-century fold-out map of Cable Telegraph Map operated under the presidency of Clarence Hungerford Mackay (1874-1938), an American financier, chairman of the board of the Postal Telegraph and Cable Corporation and president of the Mackay Radio and Telegraph Company. Clarence Mackay took over the firm from his father John Mackay in early 20th century and led it during World War I and enabled the State Department to have access to selected diplomatic traffic carried over Commercial`s cables. The company flourished for a time but in 1928, together with other elements of the Mackay System, came under the control of International Telephone and Telegraph (ITT) under a wholly owned subsidiary, the Postal Telegraph & Cable Corporation. The map draws all the commercial cables of postal telegraph in the United States and affiliations operating throughout the world, such as The Mackay System (Commercial Cable Co., Postal Telegraph Cable Co., Commercial Pacific Cable Co., Commercial Cable Co. of Cuba) and affiliated companies which include All America Cables Inc., Canadian Pacific Ry. Company`s Telegraph, Halifax & Bermudas Cable Co., Direct West India Cable Co., Eastern Telegraph and associated Companies, Great Northern Telegraph Co., Deutsch Atlantische Telegraphengesellschaft (German Atlantic Cable Co.), Italian Cable Co. [MAP COVER]: 185x115mm. Softcover with green lettering on front. Cover yellowing and slightly stained. Cover corners and spine edges bumped. Spine stained. [MAP]: 755x350mm. Cloth fold-out map. Two tiny stains and one small fingerprint-mark on map. [SUMMARY]: This extremely rare old communications map, of interest to any map collector, is in good condition.