Sweden 365 



German double flat-bar type. In Stockholm the wire used is 

 i mm. phosphor bronze of 30 per cent, conductivity and a break- 

 ing strain of 90 kilogrammes per square millimeter. Outside 

 Stockholm, in Upsala and the other towns within the yo-kilometer 

 radius, No. n B.W.G. galvanised iron wire is employed for the 

 subscribers' lines. The insulators are small double-shed, fastened 

 to their bolts with tow plugging. Joints in local wires are rarely 

 soldered, the Macintyre dry joint (fig. 99) being found satisfactory 

 enough for all purposes. Vibration in the houses is prevented or 

 reduced by slipping a length of rubber tube on each wire and bind- 

 ing it tightly with leaden strip or wire (fig. 101). The aerial cables 

 lately introduced to the extent of some twenty-five kilometers have 

 been supplied by the Fowler-Waring Cables Company, Limited ; 

 W. T. Henley & Co., Limited ; the Western Electric Company ; 

 Felten & Guilleaume, and Franz Clouth. The general specification 

 of all these cables is 102 metallic circuits insulated with paper and 

 enclosed in a leaden tube 2-25 mm. thick and 39 mm. exterior 

 diameter. The conductors are copper of -8 mm. diameter and 

 95 per cent, conductivity. The capacity of each single wire, all 

 others being earthed, is "05 mf. per kilometer. The company's 

 underground system is intended to be of an extensive nature. 

 The conduits are of the type invented by Mr. Axel Hultmann, 

 formerly chief engineer of the State telephone system (see p. 369) ; 

 the cables contain a hundred metallic circuits, with copper conduc- 

 tors of -8 mm. enclosed in a leaden pipe 3 mm. thick and 50 mm. 

 exterior diameter. They all have paper insulation and a capacity 

 of '05 mf. per kilometer. M. Aboilard, of Paris, has supplied 

 some of the cable which has been so successful in the Parisian 

 sewers for this underground work. On leaving the exchange, 

 each route will consist of Hultmann concrete conduits containing 

 eighty-six ducts of 75 mm. diameter, each duct capable of easily 

 taking a loo-pair cable. The capacity of each route will be, con- 

 sequently, 8,600 metallic circuits, which does not look as though 

 Mr. Cedergren nourished any intention of hauling down his flag 

 to the State, or had any misgiving of Stockholm's capacity and 

 willingness to continue supplying him with subscribers ad lib. 

 As they recede from the centres the conduits gradually decrease 

 in carrying power, the successive sections having seventy-six, sixty- 



