54 POPULAR SCIENCE MONTHLY 



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 ex- 

 perimental 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. 



