July, 1912 
There are four such 
schemes. One is to connect 
the mill ‘to an electric dyna- 
mo and store up the power 
in storage batteries. Another 
is to run an air compressor 
by the windmill and then use 
the compressed air for 
power. A third method is to 
make the windmill pump 
water into a pressure tank 
which would in turn force it 
to the outlets, but this device 
was planned for the purpose 
of securing a water supply 
rather than a supply of § | me i? = 
power. The fourth method B® pas Gea 
of making the windmill’s ' . ee 3 
usefulness available at all 
times is to have it pump 
water into a tank on a tower 
and then to allow the water to run from this tower down 
through a water motor and thence to the outlets, or in 
case more water is used for power than is wanted otherwise, 
allow it to run to another tank whence it is again pumped 
back to the first tank. 
With the windmill, the electric motor and gas engine are 
now the chief contenders for the honor of supplying the 
farm with power. Each system has many ardent friends, 
and the advocates who represent them always reverse the 
usual court procedure, playing the part of the prosecuting 
attorney and attempting to have them sentenced to long 
terms at hard labor, declaring their qualifications for such 
appointments in terms and figures that apparently defy 
contradiction until the other party gets the floor and enters 
his plea. reid 
Many men have no fondness for mechanics or anything 
that has to do with machinery, and to such the matter of 
picking a power plant to be lived with on one’s own prop- 
erty must often appear most mystifying and unattractive. 
This phase of the situation is, however, quite certain to 
vanish in thin air, when account is first taken of the great 
possibilities in the case and of the undoubted benefits to be 
derived. Neither college nor correspondence courses in 
physics are essential to provide an entirely adequate under- 
standing of the subject. 
Perhaps right here it may be fitting to define briefly 
the units of power measurement in which the machinery 
catalogues abound, but which enter into many men’s exper- 
iences for the first time when they approach the selection 
of a power plant for their own places. The unit of mechan- 
ical power is the horse-power, and the watt is the unit of elec- 
WEE ID 05 5 sia 
installed as that shown in the illustration to the right 
AMERICAN HOMES AND GARDENS 
A power plant equipment of this type is adapted for employment either 
on the suburban premises or for the country home 
A garage and power plant can be combined, and such an equipment 
251 
trical power. One horse- 
power is the force required 
to raise 33,000 pounds one 
foot in one minute, and a 
watt is 1-746 part of a horse- 
power. A kilowatt is 1,000 
watts or 1.34 horse-power. 
The unit of electrical pres- 
sure is the volt, which is ap- 
proximately one-half the 
pressure exerted by an ordin- 
ary dry battery. The flow of 
the electrical current is meas- 
ured in amperes, one ampere 
being the amount of the cur- 
rent that flows when a pres- 
sure of one volt is applied to 
a circuit with a resistance of 
one ohm, the name given to 
the unit of resistance to the 
passage of the current. 
Voltage, or the pressure that produces the flow of the 
current, is measured by an instrument called a voltmeter, 
while the ammeter measures the current in amperes. An 
ampere-hour is the number of amperes multiplied by the 
number of hours the current flows, while the lamp-hour 
is the number of lamps in use multiplied by the number of 
hours during which they burn. : 
The improvements of late years in the construction of 
gas and of oil engines, as well as in electrical machinery 
generally and storage batteries in particular, have accom- 
plished the perfection of small power plants to a point 
where efficiency is assured if only the simplest care is 
employed in the selection and due regard is had for the 
conditions under which work is to be done. The questions 
of first cost, and of expense of operation and maintenance 
have also been worked out greatly to the advantage of even 
the smallest farms. 
Gas engines and oil engines are made in almost any 
capacity. One leading firm builds them in sizes from one 
horse-power to 500 horse-power and is prepared to fill 
special demands for plants up to 2,000 horse-power. In 
case gasoline is too expensive as the fuel for any reason, 
other liquid fuels may be substituted, and engines are de- 
signed to use a heavier kerosene oil and alcohol. By com- 
mon consent, the internal combustion engine is the most 
eficient of all, converting a larger percentage of heat into 
mechanical energy than any other form of prime mover. 
While the efficiency of a steam plant is rarely over twelve 
per cent, that of the gas engines is commonly rated at 
twenty per cent. Alcohol is said to work as effectively in 
gasoline engines as gasoline, and one estimate has it that 
\ 
\ 
~. 
Such an equipment as this may be installed at a comparatively low 
cost in a building like that shown on the left 
ae ee 
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