AMERICAN STEAJVI ENGINEERING 279 



the use of a countershaft which cna}:)lcd any steam engine to 

 drive any set of d3^namos was nearly universal. 



As dynamo construction improved, engineers rapidly 

 perceived the advantages to be gained by doing away with 

 belts and ropes and by coupling the steam engine direct to 

 the djTiamo. America developed for this purpose a special 

 t3T)e of high speed engine, the first successful type of which 

 was the Porter-Allen engine and the peculiarity of which was 

 what is known as the fly wheel type of governor. The first 

 engines of this form were shown at the Philadelphia exhibi- 

 tion in 1876. In this form of governor, weights revolving 

 round the shaft in a vertical plane automaticall}^ vary the 

 travel of the valve and cut off by turning the eccentric round 

 on the shaft. Then follov/ed a host of inventors and of new 

 t>7)es of engines such as the Armington & Sims, the Buckeye, 

 the Mcintosh & Seymour, the Ball, the Ide, the Westingt- 

 houso, and many others. With this type of engine, however, 

 the steam economies obtained w^ith the Corliss type of valve 

 gear could not be rivalled. As dynamos grew in size and in 

 econom}^ and efficiency, and especially with the introduction 

 of electric traction and power transmission, which necessitated 

 dynamos running in many cases at an average load equal to 

 75 per cent of their rated capacity, the question of steam 

 engine and consequent fuel economy became of the greatest 

 importance. This necessity had been grasped much earlier 

 by Germany than the United States, and in 1888 Corliss 

 engines direct coupled to Siemens generators were already 

 being run to light Berlin. The first use on any scale of such 

 direct connected units was at the world's fair in Chicago, 

 in 1893, where a 1,500 kilowatt generator was mounted directly 

 on the shaft of a horizontal cross compound Allis engine run- 

 ning at 75 revolutions per minute. Then followed directly 

 the plants installed under F. S. Pearson for the Brooklyn 

 stations, and the replacing of the belted by direct driven sets 

 on the West End street railway of Boston. Vertical engines, 

 till within quite recent time, were far rarer in the United 

 States than either in England or on the continent. It would 

 seem m the light of recent experience that for properly designed 

 engines, certainly for sizes of 1,000 kilowatts and over, vertical 



