In telegraph cables, when one or two conductors “go,” it will probably be useless to look for trouble except with instruments; but if several wires are “lost” at once it will probably be found to be caused by mechanical injury, which can be located by inspection.  If it is ever necessary to loop out conductors, a joint can be readily opened and the conductors wanted picked out and connected into the branch cable and the joint again closed without disturbing the working wires.  In doing this a split sleeve must be used, and the only additional precaution to be taken is in filling the sleeve to have the insulating compound not hot enough to melt the solder and open up the split in the sleeve.  In cutting in service on light and power cables it is entirely practicable to do so without interruption of service on multiple arc circuits, even those of very high voltage; but they require great precaution and involve considerable risk to the jointer, and where possible the circuit to which the connection is to be made should previously be cut dead.  Where the voltage is not dangerous to human life, almost any service connection can be made without interruption of service.

I have only indicated a very few of the operations that may be found necessary, and the probable causes of troubles that may be encountered in the operating of underground circuits, believing that the different problems that arise can, with a little experience, be successfully met by any one who has a fair knowledge of the original construction of cable lines.—­Electrical World.

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RAILROADS TO THE CLOUDS.

If George Stephenson, when he placed the first locomotive on the track and guaranteed it a speed of six miles an hour, could have foreseen that in less than eighty years the successors of his rude machine would be climbing the sides of mountain ranges, piercing gorges hitherto deemed inaccessible, crossing ravines on bridges higher than the dome of St. Paul’s, and traversing the bowels of the earth by means of tunnels, no doubt his big blue eyes would have stood out with wonder and amazement.  But he foresaw nothing of the kind; the only problem present in his mind was how to get goods from the seaports in western England to London as easily and cheaply as possible, and to do this he substituted for horses, which had for 150 years been drawing cars along wooden or iron tracks, the wonderful machine which has revolutionized the freight and passenger traffic of the world.

It was, indeed, impossible for any one to foresee the triumphs of engineering which have accompanied the advances in transportation.  To the engineer of the present day there are no impossibilities.  The engineer is a wizard at whose command space and matter are annihilated.  The highest mountain, the deepest valley, has no terrors for him.  He can bridge the latter and encircle or tunnel the former.