An important advantage in using alcohol is its comparative safety. In case of fire oils and gasolines float on the water intended to quench a blaze; alcohol blends with that water and the flame is subdued.

Whether oil, gasoline or alcohol be their fuel, internal combustion motors gain steadily in public acceptance. On the farm they are gradually displacing the horse. An engine, which costs nothing when it is idle, shells corn, saws wood, cuts fodder, grinds feed, separates and churns cream, drives a thrasher, turns a mill, lifts water, and performs a hundred other chores quickly, simply and cheaply.

Steam and Gas Motors United.

Mr. Henry G. Stott, chief engineer of the Interborough Rapid Transit Company, New York, has recently discussed power plant economies in so thorough and suggestive a manner as to elicit the interest of engineers the world over.[42] Basing his remarks on the records of the huge plant of his Company at 74th Street and the East River, New York, he presents this table of the average losses in converting the heat from one pound of coal into electricity:—

[42] Before the American Institute of Electrical Engineers, New York, January 26, 1906.

Heat of the coal as burned, 14,150 British thermal units100.0%
Returned by feed water heater3.1
Ret„rned „ economizer6.8
109.9
Loss in ashes2.4%
Loss to stack22.7
Loss in boiler radiation and leakage8.0
Loss in pipe radiation0.2
Delivered to circulator1.6
Deli„ered t „ feed pump1.4
Loss in leakage and high pressure drips1.1
Delivered to small auxiliaries0.4
Heating0.2
Loss in engine friction0.8
Electrical losses[470]0.3
Engine radiation losses0.2
Rejected to condenser60.1
To house auxiliaries0.2 99.6
Delivered to bus-bar10.3%

Carbon dioxide (CO²) is absorbed by a solution of caustic potash. The Ados recorder based upon this absorption has enabled Mr. Stott to learn the proportion of carbon dioxide in the gases passing to the stack, the higher that proportion, the more thorough the combustion. He finds first as an element of economy careful firing, so as to avoid “holes” or thin places in a fire, through which air wastefully pours, chilling the furnace. Next in importance is adapting draft to fuel: small anthracite requires a draft of 1.5 inches of water; with a draft of but .2 inch of water one pound of dry bituminous coal has evaporated 10.6 pounds of water, with a draft of 1 inch this fell to 8.7 pounds. Mr. Stott estimates that scientific methods of firing can reduce losses to the stack to 12.7 per cent., and possibly to 10 per cent.

Respecting the loss of 8 per cent. in boiler radiation and leakage, he maintains that this is largely due to the inefficient setting of brick which, besides permitting radiation, admits much air by infiltration. The remedy is to employ the best methods of boiler setting, such as an iron-plate air-tight case enclosing a carbonate of magnesia lining outside the brickwork.

Regarding the main loss, that of 60.1 per cent. to the condenser, Mr. Stott points out that superheating could reduce this by 6 per cent. He observes that in the higher pressures of a steam cycle a reciprocating engine has an advantage, while in the lower pressures a steam turbine is more efficient. Combine them, he remarks, and use each where it is the more profitable. But in his view for the utmost economy a new type of plant should unite both steam and gas driven units.

“Over a year ago,” he says, “while watching the effect of putting a large steam turbine having a sensitive governor in connection with reciprocating engine-driven units having sluggish governors, it occurred to me that here was the solution of the gas engine problem; for the turbine immediately proceeded to act like an ideal storage battery; that is, a storage battery whose potential will not fall at the moment of taking up load, for all the load fluctuations of the plant were taken up by the steam turbine, and the reciprocating engines went on carrying almost constant loads, whilst the turbine load fluctuated between nothing and 8,000 kilowatts in periods of less than ten seconds.