BOILEE No. 6. 83 



Eesults of Tests. (Average of two days. ) Boiler No. 6. 



NOTE. The coal when fired contained 5 per cent, of its weight of water. 



The object of the tests on Boiler No. 6 was to determine the 

 effect of excluding the air from the ducts in the walls, when 

 burning a mixture of anthracite screenings and Nova Scotia 

 culm. One test was made with the passages open in the 

 ordinary manner, and another with the entrance to the ducts 

 closed. During the first test the air registers, with which the 

 fire doors were provided, were closed, and during the second 

 test the registers were open a part of the time. The compara- 

 tive tests are thus made between two systems of introducing 

 air above the fuel, one the special method for which the boiler 

 was set, and the other the common method of introducing it 

 through the fire door. The evaporative results of these tests, 

 which are an average of two days' run in each case, do not 

 show a material difference. Basing the results on the evapor- 

 ation per pound of coal , there appears to be a loss of about 2 

 per cent in closing the air ducts and using the air registers in 

 the fire door. Basing the results on the evaporation per 



