The Bolivar bulletin. [volume] (Bolivar, Hardeman County, Tenn.) 1865-1888, 1871-07-21
What is ''One-HOrse POwer.''

The use Of the word horsepower is
very common, yet few, except good me-
charles and engineers, attach a definite
meaning to it, but regarding it as indi-
eating loosely about the power ono horse
would exert. It is, however, when
used in the sense under consideration, as
definite as possible, and means the pow
or required to Lift thirty-three thousand
pounds avOirdupois one foot high in one
minute. A horse hitehed to the end of
q rope, over pulley one foot in diane
ter, placed over deep well, travelling
at the rate Of two and half miles per
hour, or two hundred and twenty feet
per minute, will draw up one hundred
and fifty pounds the same distance he
travels. The force thus eXerted is call
ed in mechanics, q horsepower" 1t be-
ing an approximation to the average of
a strong horse. II we multiply the
weight raised Zone hundred and fifty
pounds) by the number Of feet it was
moved per minute, 1.-TWO hundred and
twenty, the product will be the number
OF pounds which the same power would
raise only one foot high in the same
length Of time, (thiTty-three thousand
pounds). The dynamOmeter is an in
strument made for measuring power,
particularly that exerted in drawing.
Those used in testing the draft of agri-
cultural implements are simply very
strong balances, or spring steelyards,
graduated to indicate the power Tequir-
ed to raise any weight, within any reas-
enable limits, at the rate of two and a
half miles per hour. When we apply the
dynamometer in ascertaining the draft
of machines, if the index indicates one
hundred and fifty pounds, it is shown
that the horse is required to draw just
as hard as he would do If raising one
hundred and fifty pounds out OF a well
with rope over o palley one foot in di-
Z - III
miles per hour, and so for other weights.
The velocity at which team moves is
to DO considered, as well as the weight
| to be raised, or the load TO be drawn.
Ifa horse travels faster than two and a
| half miles in an hour, while raising one
| hundred and fifty pounds out of a we'll
he exertS more than One-hOrSe-DOyYer
exert force equal to one-horse power.
| In ascertaining the draught Of plow OF
reaper and mower, by driving faster than
/ two and half miles per hour, the dvna-
rnometer viii indicate more than the
correct draught; and by driving slower
the draught would appear to be less
than it really is. In testing the draught
/ OF machines team should always
move at the rate Of two anda half miles
an hour, or two hundred and twenty
feet per minute, which is the universe
accepted rateAwith reference to which
dynRmometers are graduated, and al
easy one to which an approximate il
driving with almost anyl Kind of rate
| Many persons have supposed that thre
hundred pounds--tWo~horse- power
/ represented the same force that a team
would exert when dragging three hun
dred pounds along the ground. 4 hOrs
can haul six hundred pounds on tn
j hard ground, with ease; but he cOul
not draw hard enough on the dynamo
meter to mark more than two hundre
and ffty, or three hundred pounds ez
. cept for segg minutes. The power Of
: man is estimated at one-fitth that Of
3 horsepower.