1 84 APPENDIX. 



boiler is new and of a form provided with a brick setting, it 

 should be in regular use at least a week before the trial, so as 

 to dry and heat the walls. If it has been laid off and become 

 cold, it should be worked before the trial until the walls are 

 well heated. 



VII. The boiler and connections should be proved to be 

 free from leaks before beginning a test, and all water connec- 

 tions, including blow and extra feed-pipes, should be discon- 

 nected, stopped with blank flanges, or bled through special 

 openings beyond the valves, except the particular pipe through 

 which water is to be fed to the boiler during the trial. Dur- 

 ing the test the blow-off and feed-pipes should remain ex- 

 posed. 



If an injector is used, it should receive steam directly 

 through a felted pipe from the boiler being tested.* 



See that the steam-main is so arranged that water of con- 

 densation cannot run back into the boiler. 



VIII. Starting and Stopping a Test. A test should last 

 at least ten .hours of continuous running. A longer test may 

 be made when it is desired to ascertain the effect of widely 

 varying conditions, or the performance of a boiler under the 

 working conditions of a prolonged run. The conditions of 

 the boiler and furnace in all respects should be, as nearly as 

 possible, the same at the end as at the beginning of the test. 

 The steam-pressure should be the same; the water-level the 

 same ; the fire upon the grates should be the same in quan- 

 tity and condition; and the walls, flues, etc., should be of 

 the same temperature. Two methods of obtaining the de- 



* In feeding a boiler undergoing test with an injector taking steam 

 from another boiler, or the main steam-pipe from several boilers, the 

 evaporative results may be modified by a difference in the quality of the 

 steam from such source compared with that supplied by the boiler being 

 tested, and in some cases the connection to the injector may act as a drip 

 for the main steam-pipe. If it is known that the steam from the main 

 pipe is of the same quality as that furnished by the boiler undergoing the 

 test, the steam may be taken from such main pipe. 



