80 BOILEB TESTS. 



The tests on Boiler No. 5 were made to determine the rela- 

 tive economy between several different kinds of coal. The 

 Cumberland coal gave the highest evaporative result and the 

 mixed coal the lowest. The evaporation per pound of Cum- 

 berland coal was 10 per cent, higher than that with Anthracite 

 coal, 28 per cent, higher than that with the mixture of pea and 

 dust and Cumberland, and 41 per cent, higher than that with 

 the mixture of pea and dust and Nova Scotia culm. Judging 

 by the percentages of ash, which are all comparatively large, 

 the coal was in each case of somewhat inferior quality. This 

 is especially marked in the Cumberland coal, which gave 11.1 

 per cent, of ash, and in both of the mixed fuels. The unfavor- 

 able effect produced by the coating of scale on the heating 

 surfaces is seen in the comparatively high temperature of the 

 escaping gases. 



An important feature of the results is the relative amount of 

 power developed by the various fuels. The dampers were 

 kept wide open during each test and the boilers produced a 

 maximum quantity of steam under each condition. The 

 Cumberland coal produced the largest amount, viz., 60 horse- 

 power, and this is 22 per cent above the nominal capacity. 

 Then comes the anthracite coal and finally the mixed fuels. 

 The mixed fuels produced 22 per cent below the rated power 

 of the boilers. Another feature is the labor involved in usin^ 



o 



the various fuels, as indicated by the number of times the 

 slicing-bar was employed in breaking up the bed of coal. The 

 anthracite coal gives the most favorable showing, while the 

 mixture of culm and pea and dust gives the least favorable 

 showing. The difference in the labor involved in slicing a 

 fire four times per day and eighteen times per day is con- 

 siderable. 



The actual economy obtained with the different fuels is shown 

 by the following table, which gives the cost of coal required to 

 generate 30,000 pounds of steam, according to quotations of 

 prices which ruled at the time of the tests. 



