14 BOILEE TESTS. 



and the dampers are closed during the night, and, in case only 

 one or two boilers of a plant are tested, the stop valves are 

 also closed, shutting the steam into the boiler. At some con- 

 venient time during the night the furnace and ash-pits are 

 cleaned. At five o'clock in the morning, or at a sufficiently 

 early hour to get up steam for the day's work, the new fire of 

 the test is started with enough pine wood to cover the grates, 

 and coal is fired at once, and the boiler brought to normal 

 action. Oftentimes the fire is in working condition before the 

 steam can be disposed of, and a pause ensues until the usual 

 work of the mill begins, during which time the fire is covered 

 with new coal, and the draught choked by shutting the damper 

 and opening the fire doors. During the noon hour, when the 

 works are stopped, the fire is cleaned (if needed) and covered 

 with new coal, and the draught checked in like manner. As 

 the hour for stopping draws near, the fires are carefully burned 

 down, so that at the close of the day's work they are nearly out. 

 As soon as they are finally extinguished, the contents of fur- 

 naces and ash-pits are removed and the doors and dampers 

 closed for the night, and in the cases noted the stop valves are 

 shut. When the coal is moist, a sample is selected and dried 

 for 24 hours, and the quantity of moisture is determined by a 

 comparison of the wet and dry weights. A sample is taken of 

 the ashes and unburned fuel removed from the furnaces and 

 ash-pits at the close of the test, and sifted through a screen 

 having |-inch meshes. The proportion of unconsumed coal 

 which fails to pass through the screen is determined and applied 

 to the total quantity, and the whole weight of unconsumed coal 

 thus found is deducted from the weight of coal fired, to deter- 

 mine the net quantity consumed. The value of the wood used 

 for starting the fires is taken to be equivalent in coal to ^o ^ 

 its weight. 



At the time of starting the new wood fire of the test, the 

 position of the water line as shown in the gauge glass of the 

 boiler is carefully noted, and the pressure indicated by the 

 steam gauge as well. At the close of the test, it is intended 

 that a sufficient amount of water shall be supplied, so that when 



