With the experience gained by an experimental system at Menlo Park, Mr. Edison began, in the spring of 1881, at the Edison Machine Works, Goerck Street, New York City, the construction of the first successful direct-connected steam dynamo. The development of an adequate underground conduit proved also most serious. The district selected for lighting was the area--nearly a square mile in extent--included between Wall, Nassau, Spruce, and Ferry Streets, Peck Slip and the East River in New York City. In those days such electrical transmission as existed--this of course related largely to telegraphy--was accomplished by means of a veritable forest of poles and wires augmented by the distribution equipments of fire alarm, telephone, burglar alarm and stock ticker companies. So used had people become to this sort of thing that even the most competent electrical authorities of the time doubted extremely whether Edison’s scheme of an underground system could be made either a scientific or a commercial success, owing to the danger of great loss through leakage. However, the Edison conduits once in use, both the public and even the telephone, telegraph and ticker companies acknowledged their feasibility. Such, in fact, was the success of the new method that the city compelled at length the removal of all telegraph poles. In the Trenches. The systematic laying out of street mains in the first company district was begun in the summer of 1881. It must not be thought, of course, that these old-time conduits resembled strikingly those of the present day. The method then used was to dig a trench in which were laid the pipes measuring twenty feet in length. Through these the conductors were drawn, two half-round copper wires kept in place first by heavy cardboard and afterward by rope. The conductors having been drawn in, a preparation of asphaltum and linseed oil was forced into the piping to serve as insulation. The spending of three and four arduous nights a week in these trenches by Mr. Edison and his associates suggests the rigor of the later European warfare. This work, together with that incident to the operation of the new station, often proved too much even for Edison’s phenomenal endurance. At such times he slept on a cot close beside the running engines, while the rest of the crew crawled in on the lower row of field-magnet coils of the dynamos, a place warm enough, though a trifle bumpy. One of the inventor’s early assistants tells of going to sleep standing up, leaning against a door frame--this, after forty-eight hours of uninterrupted work. [Illustration: THE DYNAMO ROOM OF THE FIRST EDISON ELECTRIC LIGHTING STATION IN NEW YORK]