One of the most extraordinary pages in Sir David Brewster’s _Letters
on Natural Magic_ is the experiment in which a heavy man is raised
with the greatest facility when he is lifted up the instant that his
own lungs, and those of the persons who raise him, are inflated with
air. Thus the heaviest person in the party lies down upon two chairs,
his legs being supported by the one and his back by the other. Four
persons, one at each leg, and one at each shoulder, then try to raise
him--the person to be raised giving two signals, by clapping his hands.
At the first signal, he himself and the four lifters begin to draw a
long and full breath; and when the inhalation is completed, or the
lungs filled, the second signal is given for raising the person from
the chair. To his own surprise, and that of his bearers, he rises with
the greatest facility, as if he were no heavier than a feather. Sir
David Brewster states that he has seen this inexplicable experiment
performed more than once; and he appealed for testimony to Sir Walter
Scott, who had repeatedly seen the experiment, and performed the part
both of the load and of the bearer. It was first shown in England by
Major H., who saw it performed in a large party at Venice, under the
direction of an officer of the American navy.[9]
Sir David Brewster (in a letter to _Notes and Queries_, No. 143)
further remarks, that “the inhalation of the lifters the moment the
effort is made is doubtless essential, and for this reason: when we
make a great effort, either in pulling or lifting, we always fill the
chest with air previous to the effort; and when the inhalation is
completed, we close the _rima glottidis_ to keep the air in the lungs.
The chest being thus kept expanded, the pulling or lifting muscles have
received as it were a fulcrum round which their power is exerted; and
we can thus lift the greatest weight which the muscles are capable of
doing. When the chest collapses by the escape of the air, the lifters
lose their muscular power; reinhalation of air by the liftee can
certainly add nothing to the power of the lifters, or diminish his
own weight, which is only increased by the weight of the air which he
inhales.”
“FORCE CAN NEITHER BE CREATED NOR DESTROYED.”
Professor Faraday, in his able inquiry upon “the Conservation of
Force,” maintains that to admit that force may be destructible, or can
altogether disappear, would be to admit that matter could be uncreated;
for we know matter only by its forces. From his many illustrations we
select the following:
The indestructibility of individual matter is a most important case
of the Conservation of Chemical Force. A molecule has been endowed
with powers which give rise in it to various qualities; and those
never change, either in their nature or amount. A particle of
oxygen is ever a particle of oxygen; nothing can in the least wear
it. If it enters into combination, and disappears as oxygen; if it
pass through a thousand combinations--animal, vegetable, mineral;
if it lie hid for a thousand years, and then be evolved,--it is
oxygen with the first qualities, neither more nor less. It has
all its original force, and only that; the amount of force which
it disengaged when hiding itself, has again to be employed in a
reverse direction when it is set at liberty: and if, hereafter,
we should decompose oxygen, and find it compounded of other
particles, we should only increase the strength of the proof of the
conservation of force; for we should have a right to say of these
particles, long as they have been hidden, all that we could say of
the oxygen itself.
In conclusion, he adds:
Let us not admit the destruction or creation of force without clear
and constant proof. Just as the chemist owes all the perfection
of his science to his dependence on the certainty of gravitation
applied by the balance, so may the physical philosopher expect to
find the greatest security and the utmost aid in the principle
of the conservation of force. All that we have that is good and
safe--as the steam-engine, the electric telegraph, &c.--witness to
that principle; it would require a perpetual motion, a fire without
heat, heat without a source, action without reaction, cause without
effect, or effect without cause, to displace it from its rank as a
law of nature.