‘ ty of the power he to that of the weight still

 ‘

 

~—.—..

 

    
      

    
 

    
  

. _ .

To contrit-e :1 Proper illackine thatshall maven ‘ 2. But the proportion of the velocity of

oz «C-r‘t'vc7z Weiglit with a G55-z.~e7z Pczzzer, or,'!the power and weiglit must not be made too
with (2 Given ‘Quantity of Force, shall one-z'»llgreat neither. For itlis a fault to give a. ma-
comc any other Given Resistance. ,[From,‘chiuc too much power, as well as too little :
E.n3rsou’s Principles of ll’IeCll.8.l]i(_3S.] ‘ l for if the power can rai.=.ie‘the weight, and
If the given power is notable to over-I overcome the resistance, and the engine per-
come the given resistance, when directly ap- {form its proper effect in a convenient time,
plied, that is, when the power applied is lessland works well, it is isulilcient for the end
than the weight or resistance given, then the proposed. And it is in vain to make more
thing is to be performed by the help of a ma; additions to the engine, to increase the -popwer
chine made with Zeoerxv, wheels, pullies, screws,; any fhrther; for that would -not only be a
6930., so adjusted, that when the weight audl needless c:-zpense, but the engine would lose
power are put in motion on the machine, the, time in working. i , ~
velocity of the power may be at least so 3. As to the power applied to work the en-
much greater than that of the weight, as the gine, it may be either a living power, as men,
weight and friction of the machine, taken to- horses, «.Szc., or an artificial power, as a
gather, is greater thanthe power. For on‘ Spring, or.c., or a natural power, as wind,
this principle depends the mechanism or con- water, fire, weights, «Sac. - “
trivance of mechanical engines, used to draw When tl1e.quan$.»'ty of the power islmown,
or raise heavyibodics, or overcome any other it matters not, as to the effect, what kind of
force. The whole design of these being to power it‘ is. For the same quantity, of any
give such a velocity to the power in respect sort will produceithe same effect ; -and differ-
ofihe weight, as that the inomentum of the entsorts of powers may, be applied, in an
power may exceed the momentum of the equal quantity, :1 great. variety ot‘wa_vs.
weight. V For, if machines are so cozitrivecl The most easy power applied to a machine
that the velocities of theagent and resistant is weight, if it be capable of effecting the
are reciprocally as their "forces, the agent thing designed. If‘not, then wind, water,
will just sustain the resistant; but, with o &c.,iif that can conveniently be had, and
greater ‘degree 0i"ve‘locfity,.will overcome it. without much expensp. l‘
S3 that,‘iE‘ the excess of velocity in the power V A spring is also a convenient moving pow-
is so great as to overcome iall-that resistance or for several machines ; but it never acts
which commonly arises from the friction or ._equ-al’l'y', as, a weight does ;; but is stronger,
attrition of contiguous bodies, as they slide-by
one another, or from the ‘cohesion of borliee
that are to be separated, or from the weights
of bodies to be raised, the excess-.0? the-force
remaining, after all these resistances are
overcome',- will produce an acceleration of
motion proportional thereto, as well in the
parts of the machine, as in the resisting body.
Now, how a machine may, be contrived to
perform this to the best advantage will ap-
pear from the following rules : ’ ~
1. Having assigned the pro'portio’nof' your
power and the weight to be raisecl, the ‘next
thing is to consider how to combine lovers,
wheels, pullies, _&c., so that, working to-
gether, they maybe able to give a,velocity'
to the power, which shall be, to that of the
weight, something greater than in the pro-
}‘)'Jl‘il03 of the weight to the power. ’ This
done, you must ‘estimate your ‘quantity of
friction, by the last prop. ; and if the veloci-

nnd that in proportion to the degree of bond-
ing, or the distance it is forced to. But
springs grow weather by otleri bencling, or re-
maining long bent; yet they recover‘ part
of their strength by lying unbent.

The natural powers, wind and water, may
be applied with vast advazitage tothe work-
ing of great engines, when Inanaged with
sltill and judgment. The due application of
these has much aliridged the labors of men;
for there is scarce any labor to be perform.-
ed, but an ingeii'ioxzs artificer can tell how to
apply tliccc powers to execute. his design,
and answer his purpose. For any constant
motion being given, it K-,l‘i.1lly,, by a due appli-
cation, be made topprorluce any other mo.
tions we desire. , 'I‘lieret"ore, these. powers
are the most easyiand‘ us-ot'ul, and of the
greatest benefit to niankind. Besides, tlioy
cost .notbi_ng, nor require any repetition or
reiiewirig, like 3. Weiglit or it sp1'iii_.g;§,.wlihali
réquire«to,l.-e wound up. VVhr.~.n these can.
not be had, or caches: sex?“-.*-:=. our om}, we llavla
recourse to some liv,i:i;; power, as men,
horses,  ‘ i r »

r 4. Men may apply. their strength several
ways, in worlzing c rnacliim}. A man of or-

in a greater proportion than the weight and
f.-ictiori taken together is to the power, then
your macliine will be able to raise the'weight.'
Anffl, note, this ,proportion_ must be so much
greater, as you wouldliave your engine work
faster. V’ ’ V A A »

,   AMERIQAN _9na1LRoAoJoURNAL. A _l§D'

dinary strength, turning a
die, can act for a whole day against a resist. ,

or more.

when much bent, than when but at little bent, *

roller by the hair.

once ‘equal to 30 lbs. weight; and, if he
works ten hours in a day, he will raise a.
weight of 30 lbs. 3% feet in a second; or, if
the weight be greater, he will raise it so much
less in proportion. But a man may act, for
a small time, against a resistance of 50 lbs.,

If two men work at a Windlass, or roller,
they can more easily draw up 70 lbs. than
one man can 30 lbs., provided the elbow of
one of the handles be at right angles to that
of the other. And, with a fly or heavy wheel
applied to it, a man may do one-third‘ part

80 lbs., and work a wholclday when the re.
sistance is but 4!) lbs.

Men used to carrying, suchas porters, will
carry, some 150 lhs., others 200 or 250lbs.,
according to their strength, , o ~ ,
A. man can draw about 70 or 80 lbs. ho.

his weight. .

If the weight ofa man be 140 lbs.‘ he can
act with no greater :1 force in thrusting ho-
rigcontally, at the height of his shoulders, than
27 lbs. ‘ - ‘

iug, as strong aslfivc men.
ry :3-10 or 270 lbs.

A liorsc draws to greatestztdvantagc when
the line ofdirection is a little elevated above
the horizon, and the power acts against his
breast ; and can draw 200 lbs. for eight
hours in a day, at two miles and a half in an
hour. If he clraxv 240 lbs. he can work but
six hours, and not go quite so fast. And, in
both cases, if he carries some weight, he will
draw better than if he carried none. And
this is the weight a horse . is supposed to be
able to draw over a pulley, out of a well. In

A horse will car-

? a cart, :1 horse may draw 1000 lbs.

The most force a horse can exert is when.
he draws something above a horizontal po-
sition. . o - p .

The worst way of applying the strength of
a horse is to make him carry or draw up
hill. - And three men, in a steep hill, carry-
ing each 100 lbs., w'll climbup faster than "a.
horse with 300 lbs.

Though a horse may draw in a round
walk of 18 feet diameter, yet; such a, walk»
should not be less than £25 or 30 feet dia-
meter. .

5. Every machine ought to be made of as
few parts. and those  simpleias possible, to
answer its pizrposo; not only because the ex-
pense of making and repairing will. be less,
but it will also be less liable to any disorder.

And it is l1C9:.llt3SS -to do 1:. thing with many, ’

which niay be done with fewer parts. , .

6. If a weight is to be raised but a very
little way, the lover is the In():’:ll. simple, easy,
and ready machine. Or if the weight be
very great, the common screw is most pro-
ner. But if the weight is to be faised agreat
way, the wheel and axle is aproper power,
and blocks and pullies are easier still; and
the shine may be done by the help of the pet-
petual screw.

Great wheels, to be wrought by men or
cattle, are of most use and convenience when
their axles are perpendicular tr) the horizon;

their axles liorizontal.

chines together, to malac L a compound‘ one :-

Iliough the lever, when simple, cannot:1*a.isei

more work, and, for a little while, act with it»
force, or overcome a continual res1stance,,of A

ll'ii‘.0!1l11lly; for he can but apply about half,

As to l1oi'ses : e A horse is, generally speak-'

but if by water, &c., then it  boat to have .

7. As to the combination of simple ma-W