48 BOILEB TESTS. 



The highest cost in the comparison attends the use of anthra- 

 cite chestnut coal, and the lowest that of a mixture of two 

 parts pea and dust and one part Nova Scotia culm. The pure 

 Nova Scotia culm stands about on a par with the mixture. 



If the Nova Scotia coal and the mixture containing Nova 

 Scotia coal are left out of the comparison, the mixture of pea 

 and dust and Cumberland coal takes the lead as the cheapest 

 fuel, and the Cumberland follows closely upon it. These 

 figures show that at prices which now hold, little is gained by 

 the use of a mixture of either pea and dust and Cumberland or 

 of pea and dust and culm. Either of the bituminous coals 

 fired without mixture produces nearly as good results. Con- 

 sidering the fact that the use of the mixed fuel reduces the 

 available power of the boiler, the pure coal easily has the 

 advantage ; no one would go to the trouble of using an inferior 

 grade of coal, such as the best pea and dust mixed with 

 bituminous coal is, and such as much of it is liable to be, 

 unless by so doing a material reduction in cost could be 

 attained. If yard screenings can be delivered at $2.75 per 

 ton, and if it secures the same result as pea and dust coal, the 

 total cost of fuel and labor when a mixture of two parts 

 screenings and one part Cumberland coal is used amounts to 

 $65.69 per day, and this sum is lower than any quantity given 

 in the table. 



Pea coal conies next to Cumberland in the order of cheap- 

 ness, though the difference is trifling, and then the anthracite 

 broken coal. 



An important matter relating to the use of different kinds of 

 coal is the relative amount of power which they give when 

 fired in the same boiler. Boiler No. 5, rated at 54 horse- 

 power (on the basis of 12 square feet of heating surface) , gave 

 60 horse-power with Cumberland coal, 53.9 horse-power with 

 anthracite broken, and 38.5 horse-power with a mixture of 

 two parts pea and dust and one part Cumberland, the damper 

 being wide open in every case. Boiler No. 9, rated at 74 

 horse-power with 3-8 inch draught suction, gave 143.8 horse- 

 power with Cumberland coal, 105.5 horse-power with anthra- 



