366 Telephone Systems of the Continent of Europe 



two, thirty-eight, and finally twelve ducts. Manholes occur about 

 every 100 meters ; they are cast in concrete of an elliptical shape 

 and fitted with suitable cast-iron covers. This underground scheme, 

 like all Mr. Cedergren's notions, is conceived on a grand scale, and 

 will assuredly succeed. The submarine work necessary in and 

 near Stockholm is usually done with armoured cable containing 

 from four to fourteen pairs insulated with vulcanised rubber. 



State system. The State local work is very similar to the 

 General Company's, except that the phosphor bronze is of i -25 mm. 

 diameter. The insulators are the same, and joints are not soldered. 

 The standards, too, bear a family likeness, and fig. 128 will serve 

 to illustrate those of both systems. The uprights are of double, 

 the arms of single, channel steel. The fastening is done by sole- 

 plates adapted to the slope of the roof and bolted through to the 

 rafters. Sometimes, heavily laden standards are strutted in the 

 Belgian fashion (figs. 22 and 23, Belgian section) ; if not so 

 strutted they are carefully stayed. The Swedish and Norwegian 

 mode of construction with channel iron or steel is unquestionably 

 stronger, if heavier, than the tubular methods employed in Great 

 Britain, Germany, and Holland. Tubes collapse when subjected 

 to a sudden and heavy strain, such as is likely to result from the 

 failure of a span of wires or of an adjacent standard, and crumple 

 up beyond repair ; the channel steel, being solid, may bend, but 

 cannot collapse, and is consequently better adapted to withstand 

 accidents, and, if injured, may be readily straightened again. On 

 the other hand, it is more costly to make and transport, heavier to 

 handle during erection, and permanently severer on the roofs. 

 Fig. 129 shows a typical Swedish double ground pole, fitted with 

 angle-iron arms, of solid and good construction. It is not the 

 practice in Sweden to earth-wire either standards or ground poles. 

 The State, like the General Company, has recently taken to 

 aerial cables. Those erected are by Felten & Guilleaume, and con- 

 tain thirty-eight pairs covered with jute and then with lead. The 

 submarine type of cable is insulated with vulcanised rubber and 

 armoured in the usual way. 



A considerable proportion of the State local work is under- 

 ground. The conduits are those originally designed for the pur- 

 pose by Mr. Axel Hultmann, late engineer to the State telephone 



