What effect do you want to produce?
The object of the science of mechanics is either the application or the neutralization of the laws of motion.
As for motion pure and simple, I tell you humbly, that we cannot possibly define it.
That disposed of, unvarying phenomena have been observed which accompany the actions of solids and fluids.
If we set up the conditions by which these phenomena are brought to pass, we can transport bodies or communicate locomotive power to them at a predetermined rate of speed. We can project them, divide them up in a few or an infinite number of pieces, accordingly as we break them or grind them to powder; we can twist bodies or make them rotate, modify, compress, expand, or extend them.
The whole science, sir, rests upon a single fact.
"You see this ball," he went on; "here it lies upon this slab.
Now, it is over there.
What name shall we give to what has taken place, so natural from a physical point of view, so amazing from a moral?
Movement, locomotion, changing of place?
What prodigious vanity lurks underneath the words.
Does a name solve the difficulty?
Yet it is the whole of our science for all that.
Our machines either make direct use of this agency, this fact, or they convert it.
This trifling phenomenon, applied to large masses, would send Paris flying.
We can increase speed by an expenditure of force, and augment the force by an increase of speed.
But what are speed and force?
Our science is as powerless to tell us that as to create motion.
Any movement whatever is an immense power, and man does not create power of any kind.
Everything is movement, thought itself is a movement, upon movement nature is based.
Death is a movement whose limitations are little known.
If God is eternal, be sure that He moves perpetually; perhaps God is movement.
That is why movement, like God is inexplicable, unfathomable, unlimited, incomprehensible, intangible.
Who has ever touched, comprehended, or measured movement?
We feel its effects without seeing it; we can even deny them as we can deny the existence of a God.
Where is it?
Where is it not?
Whence comes it?
What is its source?
What is its end?
It surrounds us, it intrudes upon us, and yet escapes us.
It is evident as a fact, obscure as an abstraction; it is at once effect and cause.
It requires space, even as we, and what is space?
Movement alone recalls it to us; without movement, space is but an empty meaningless word.
Like space, like creation, like the infinite, movement is an insoluble problem which confounds human reason; man will never conceive it, whatever else he may be permitted to conceive.
"Between each point in space occupied in succession by that ball," continued the man of science, "there is an abyss confronting human reason, an abyss into which Pascal fell.
In order to produce any effect upon an unknown substance, we ought first of all to study that substance; to know whether, in accordance with its nature, it will be broken by the force of a blow, or whether it will withstand it; if it breaks in pieces, and you have no wish to split it up, we shall not achieve the end proposed.
If you want to compress it, a uniform impulse must be communicated to all the particles of the substance, so as to diminish the interval that separates them in an equal degree.
If you wish to expand it, we should try to bring a uniform eccentric force to bear on every molecule; for unless we conform accurately to this law, we shall have breaches in continuity.
The modes of motion, sir, are infinite, and no limit exists to combinations of movement.
Upon what effect have you determined?"
"I want any kind of pressure that is strong enough to expand the skin indefinitely," began Raphael, quite of out patience.
"Substance is finite," the mathematician put in, "and therefore will not admit of indefinite expansion, but pressure will necessarily increase the extent of surface at the expense of the thickness, which will be diminished until the point is reached when the material gives out——"
"Bring about that result, sir," Raphael cried, "and you will have earned millions."
"Then I should rob you of your money," replied the other, phlegmatic as a Dutchman.
"I am going to show you, in a word or two, that a machine can be made that is fit to crush Providence itself in pieces like a fly.
It would reduce a man to the conditions of a piece of waste paper; a man—boots and spurs, hat and cravat, trinkets and gold, and all——"
"What a fearful machine!"
"Instead of flinging their brats into the water, the Chinese ought to make them useful in this way," the man of science went on, without reflecting on the regard man has for his progeny.
Quite absorbed by his idea, Planchette took an empty flower-pot, with a hole in the bottom, and put it on the surface of the dial, then he went to look for a little clay in a corner of the garden.