BOILER No. 36. ]51 



by itself it represents excellent work, In view of the new 

 condition of the boiler, however, these tests cannot be held to 

 show special advantage due to the use of a detached furnace. 

 Comparing the results of the coal tests with each other, the 

 evaporation per pound of Cumberland coal is 8.1 per cent, 

 greater than that per pound of anthracite coal ; and the evap- 

 oration per pound of the mixture is 1 per cent, greater. 

 Basing the comparison on the cost of fuel, the cost of coal 

 required to produce a given amount of steam is 8 per cent, 

 less when Cumberland coal is used, and 23.5 per cent, less 

 when mixed fuel is used, than that of anthracite coal. The 

 prices on which these figures are obtained, per ton of 2,240 

 pounds, are $4.50 each for anthracite and Cumberland, and 

 $2.75 for screenings. 



The apparatus used for supplying the petroleum to the fur- 

 naces consisted of four injectors, to which the oil was brought 

 by means of a steam pump. The injectors or burners were 

 placed in a horizontal position in the front wall of the furnace, 

 and pointed toward the middle of the arch. They consisted 

 of two wrought iron tubes one within the other. The outer 

 one carried the oil, and the inner one was arranged so as to 

 supply a jet of steam, by means of which the oil was properly 

 distributed as it entered the furnace. The amount of steam 

 used by the pump and jet was 4.5 per cent, of that generated 

 by the boiler. After deducting this from the total evapora- 

 tion, the net amount of water from, and at 212 degrees evap- 

 orated per pound of oil was 13.66 pounds. This quantity is 

 34 per cent, more than the evaporation per pound of anthra- 

 cite coal, and 24 per cent, more than the evaporation per 

 pound of Cumberland coal. With Cumberland coal at $4.50 

 per ton (2,240 pounds), the price of oil required to make 

 the cost of fuel for producing a given amount of steam the 

 same in both cases, is 1.8 cents per gallon. 



The result obtained with the residuum is probably inferior 

 to that which would be obtained with the crude oil itself. 

 This oil came from Pennsylvania. A test made on another 

 boiler with oil which was obtained from wells in Canada, gave 



