Petroleum as Fuel. 19 
weight of oil to the boiling point—212 deg. ; thus the 
weight of oil which was requisite to heat ove cubic foot of 
water ove degree was $2,'s. —8°39 pounds ; and the weight 
of oil which was requisite to heat ove cubie foot of water 
one degree was %i0=0019 pounds. This multiplied 
by 1,119 deg. 2,126, and this by the 200 cubic feet of 
water in the boiler gives 425 pounds, as the weight of owl 
which would convert the contents of the boiler into steam at 
the atmospheric pressure—otz00 + 9°24=29'33 pounds, as the 
weight of water at a temperature of 60 deg., which will be 
converted into steam by one pound of oil. From Isher- 
wood’s valuable experiment on marine boilers,—we find 
this same type of boiler in use on board of the United 
States steamers—and from the mean of the experiments 
conducted on these boilers, we find the quantity of water 
evaporated from a temperature of 100 deg. with steam at 
the pressure of the atmosphere by one pound of anthra- 
cite coal, to be 85 pounds. To compare this with the ~ 
evaporation made from a lower temperature of water by 
means of the oil, this weight must be reduced in the follow- 
ing ratio, established by Isherwood: ge $38 7343 Gee —3852— 
0964, ‘which multiplied by 85, gives 8:16 as the weight 
of water at 60 deg., converted into steam of atmospheric 
pressure by one pound of anthracite coal. 
Comparing this result with that above shown for the pro- 
duct of the combustion of oil, we find the evaporating power 
of the two fuels to be in favour of the oil, in the ratio of 
29°33 to 816, or 36, weight for weight ; the coal and the 
oil occupying about the same space for a given weight. 
That is to say. a cubic foot of coal as stowed aboard ship, 
will weigh about the same, or a little less, than a cubit foot 
of oil, thefirst weighing from forty-three to fifty-two pounds, 
and the latter about fifty-four pounds to the cubic foot. 
Further experiments, with improved apparatus, will be 
necessary in order to determine the precise economic value 
of this fuel in comparison with coal, but the advantages of 
the oil as a fuel for marine engines may be briefly summed 
up as follows :—- 
Rapidity with which steam may. be raised—reduced 
dimensions of boiler and furnace below that required for coal 
—the continuous firing effecte1 by feeding the fuel through a 
pipe into the furnace, thereby preventing the great loss of 
heat in the furnace every time a fresh supply of coal is 
thrown on, and the rush of cold air upon the opening of the 
furnace doors—the freedom from smoke, cinder, ash, or re- 
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