Milford chronicle., 1914-03-13
TANNING The SAILS
No Amount Of Wind Raised
Aboard a Ship Can Propel 1t.
CONTRARY TO GATURAL LAW.
As a Matter Of Fact, the Force Of the
Air Driven Against the Canvas
Would Have a Tendency to Send tho
Vessel Backward Instead Of Forward.

III an electric fan could be made
large enough TO throw a sufficient
amount Of wind to move a small sa4.
boat and such fan was placed on the
end Of a boat with the wind n'om the
fan blowing against tie sail on the
very boat the fan is on. is It possible
that 1t could move the boat? The ar
gument is that the fan. being on the
same boat as the sail. cannot move
itself. But as the air detaches itself
from the fan and hits the sail. my idea
Is that it can. provided 1t has the
strength TO move the boat. Please give
an answer"
This question is worth answering be-
cause It involves a principle Of physics
that ought TO be universally under
stood and ignorance Of which may lead
to the waste OF both time and money
upon inventions that will not work.
The writer OF the question thinks
that because the air. as she expresses
it, Is detached from" the fan when It
starts of to strike the sail. 1t ought to
act ike an ordinary wind and push the
boat before It. But she would not think
so II she reflected that the particles Of
air driven from the fan resemble a
swarm Of bullets shot from a gun.
The air particles get their force from
the fan as the bullets get theirs from
the gun. aud just as the gun recoils
with a force equal to that which it i'm
parts to the bullets. so the fan. wheth-
er driven by electricity OF steam or
turned by hand inevitably recoils with
the same amount Of force that it i'm.
parts to the air
70 make clearer the comparison be
tween Il stream Of bullets from a gun
and a stream Of wind from an electric
fan, imagine q Maxim gun placed at
the rear of a boat and an impenetrable
target at the front and then suppose
that the gun should hurl a continuous
current of bullets against the target
Anybody can see that the boat would
not be driven forward because the
recoil Of the gun would constantly
force it backward With the same
energy with which the bullets. striking
the target. forced 1t ahead.
But II the gun were placed on shore
or on another support its stream OF
bullets striking the target would drive
the boat forward. because then their
effect would be like that OF wind
blowing freely across the water and
having no connection with anything on
the boat.
An ordinary wind is able to drive a
boat whose sail it strikes because its
reaction THAT of the windl Is not upon
the boat. but upon the great mass Of
the atmosphere or upon the earth.
The principle to be remembered.
and ignorance or forgetfulness Of
which has cost the happiness Of more
than one uneducated inventors life, Is
that no mechanical force can be pro-
duced without an expenditure Of en-
ergy precisely equivalent Never for
get thnf there can be no action with
out equel reaction and that If the ac-
tiOn takes its origin within the limits
Of the thing that is acted upon the
reaction will also be felt within those
same limits.
Your electric fan won,d drive q toy
vessel placed on the deck OF your
boat, although II would not drive the
boat itself. because. with regard TO
the toy vessel. the breeze from the fan
would have an independent origin. like
an ordinary wind blowing over a lake,
and its reaction would not be upon
the toy. but upon the boat over whose
deck the toy glided.
II you are inside a car and push upon
the car you cannot move it as you could !
II you stood upon the ground outside |
and pushed In the first case your /
action and reaction are both upon the |
car but in the second case The action |
Is upon the car and the reaction upon /
the ground outside. The same thing ]
happens If you suspend a bar above |
your bead aud lift yourself by pulling |
down on It. and afterward put the bar |
under your feet and try to lift yourself /
by pulling up on IT, You succeed in
lifting yourself Ia he first caSe. but 4
you fail in the second. because when
he bar Is under your feet the force
,f your pull reacts upon your own
body and urges it down just as much
Is up.
There is one effect Of the elevtrlc fan
which might surprise yOu-it would
end to drive your boat backyard in
ltead OF forward. Il would push
lgainst air like the propeller OF an
lerOplane. and to make 1t drive your
boat forward you would have to face
he fan around. so that its reaction
would be upon the atmosphere behind
instead Of ahead Of the boat. and in
ither case your sail would be not only
Useless but an encumbrance.-Garr
?. Serviss IN New York Journal