Publication: Western Electrician
Chicago, IL, United States
Telegraph Construction in African
The construction of the telegraph system in the Belgian Congo territory in Africa, which has been carried out since 1894, presents some interesting features, owing to the peculiar conditions of the country. The personnel is nearly all native, and is divided into companies of 40 men, each directed by one or two Europeans. From Boma to Leopoldville the line is formed of two phosphor-bronze wires of two millimeters diameter. To protect the wire from the cupidity of the natives it is covered with a blackish paint. The wire is mounted on steel posts placed 300 feet apart; they are 22 feet high and formed of T-iron, weighing about 11 tons each. At the upper end are three holes, two for the insulators and the third for the brace wires. The insulators, of the Belgian state type, are also of a dark color, to attract less attention. The length of the span has been increased over that of the former lines by using a harder wire, reducing its conductivity to 80 per cent., while the breaking strain is increased to 158 kilograms per square millimeter. Where the line passes through the forest or bush a path 30 feet wide has been cut in order to protect it from forest fires.
At Underhill, where the line crosses the river, a single span is used, mounted upon two towers of angle iron in trellis construction, 50 feet high. As the span is 2,500 feet long, the line wire is supported from four steel wires having a breaking strain of 314 kilograms. The Kassai River is crossed in two spans, with a central tower supported on a small island in the middle of the river. The three towers are respectively 45, 120 and 125 feet high, and the spans are 1,400 and 2,200 feet long.
The line is equipped with three main offices, nine telephone stations and six telephone cabins for the use of fhe steamer captains. For the inspection of the line there are 50 stations, the line being divided into five sections. Each section has a corps of five inspectors with a European chief. The outfit of the Congo telegraph stations includes a table with removable legs, a Morse receiver, Leclanche cells, an indicating galvanometer, key and sounder, etc. The main telephone posts are provided with microphones of the granular type, with two Leclanche cells, a magneto, bell and annunciator. In the telephone cabins, which are elevated above the ground on posts, so as to be out of the reach of white ants, there is a complete telephone set with dry cells and a special form of switch with points marked 1, 2 and 3. After taking down the receiver from the hook the switch is placed on I or 2 to connect with the preceding or the following post. After the communication, the receiver is hung up and the handle falls automatically to 3, which makes direct connection between the two neighboring posts. Many difficulties have been met with in the construction of the line, among these being the cupidity and prejudice of the natives, who consider it as a fetich, and when the wire passes over their houses make haste to move out. A great cause of trouble has been the elephants, which rub against the posts and overturn them. The elephants often uproot the posts with their trunks and twist them into corkscrew shape. In this way many miles of line have been destroyed.