ENGINE No. 58. 231 



Engine No. 58 is a cross compound with horizontal un- 

 jacketecl cylinders and a reheating receiver. The condenser is 

 of the jet type with an independent steam driven air-pump, the 

 quantity of steam used by which was determined and allowed 

 for. The steam is taken from water-tube boilers, and at the 

 throttle valve was found to contain .2 of one per cent of mois- 

 ture. The load was an electric generator carried by the fly- 

 wheel shaft, and on Test " A " the current was consumed in a 

 water rheostat, while that of Test " B " was used by the motors 

 of an electric street railroad, and the load was variable. The 

 valves and pistons were in an unusually tight condition 

 throughout. 



The weight of steam condensed in the reheater coil on 

 test "A" was 500 Ibs. per hour, or about .5 of a pound per 

 I. H. P. per hour ; and this is included in the quantities given 

 in the tables. In the diagrams which are appended for the 

 variable load test, the two extreme lines are reproduced which 

 were taken for a period covering ten consecutive revolutions. 

 During the whole trial with variable load, the maximum varia- 

 tion of the load was shown by the extreme readings of the 

 ammeter. The highest was 1,456 amperes and the lowest 624. 

 The next highest readings were 1,300 amperes, and the next 

 lowest 669. 



* These figures were determined from ten sets of diagrams, the average 

 horse-power developed by the whole engine being 1029.16. The average 

 horse-power used for working up the results (1030.0) was determined from the 

 average electrical readings, using the efficiency corresponding to the readings 

 when the ten sets were obtained. On the variable load test the horse-power 

 was determined from the electrical readings by using the average efficiency 

 found by independent tests made with a steady load, this load being the average 

 load of the main trial. 



