were connected up and used as dynamos in lighting his factory. In 1875 he brought out a more compact dynamo that 'was in operation furnishing current for electric lights in Machinery Hall during the entire period of the Centennial.' In 1877 two Brush 'dynamos built for lighting were exhibited and tested at the Franklin Institute in Philadelphia,' with a 'ring-clutch' arc lamp. The first Brush 'dynamo and lamp actually sold were shipped to Dr. Longworth, of Cincinnati, about January, 1878,' and installed by Charles F. Brush. In April, 1879, twelve Brush lamps were installed in Cleveland for street lighting, and 'on December 20, 1880, Broadway, New York, from Fourteenth to Twenty-sixth street was first lighted with fifteen Brush lamps,' The first Edison central station was opened in New York on September 4, 1882.
Ten years after the opening of the first telephone exchange central electric-lighting stations were in operation in all principal cities. Of electric railways, in the beginning of 1887, in the United States 'there were only ten installations with an aggregate of less than forty miles of track and fifty motor cars, operated mostly from overhead lines with traveling trolleys.' The principal practical pioneers were Charles J. Van Depoele who built an experimental trolley system in Chicago in 1882-83; Leo Daft who, a year later, operated an experimental electric locomotive at Saratoga; Bentley & Knight who placed an experimental conduit system in operation in Cleveland, in August, 1884; J. C. Henry who completed the trolley system in Kansas City in 1884-85, and Frank J. Sprague's experiments in 1885.