A necessary cause is one which cannot be conceived of as having power to act differently from its actual developements--fire must burn--gravitation must draw bodies towards the earth's centre.
The nisus ofgravitation we do not observe; we observe merely the facts of gravitation.
The law of gravitation is one of the most universally operative; but every bird rising upon its wings, every dog in its leaps, yea, the grasshopper springing from the earth, sets this law at defiance.
Thus it is that Louis Napoleon intends to bring us within the centrifugal gravitation of the European balance of power.
And he discovers the law of gravitation which governs the existence of every material atom in the universe.
With my law of gravitation I point to a speck in space and say: "You'll find a new planet there," and you find it.
The feeble-minded agnostic seizes the law of gravitation and thinks he can discard God with gravity's help.
Within the earth the stress that arises from the mutual gravitation of the parts is very great.
The chemical agencies of water and air are assisted by those of electricity; and their joint effects combined with those of gravitation and the mechanical ones I first described are sufficient to account for the results of time.
The water, raised in vapour by the solar heat, is precipitated by the cool air in the atmosphere; it is carried down by gravitation to the surface, and gains its mechanical force from this law.
It is sometimes said by such persons, that the discovery of the law of gravitation was owing to accident: and a ridiculous story is told of the falling of an apple as the cause of this discovery.
The ordinary phenomenon of gravitation is no whit more mysterious, in all truth, than that which we were now witnessing--but we are born to it!
It was because people did not know about gravitation that they laughed at Columbus when he said the earth was round.
And the pull of these particles out from the center is stronger than the pull of gravitation on the edges of the top to make it tip over; so it stands upright while it spins.
Now about the place wheregravitation has no effect.
At the same time it is this gravitation of the sun that keeps the earth from flying off into space, where we should all be frozen to icicles and lost in everlasting night.
Again let us imagine ourselves up in the place where gravitation has no effect.
He would come to the conclusion that no creature could possibly exist on the Earth, as the tremendous force of gravitation with great atmospheric pressure would forbid the existence of any organic forms.
The Moon without air remains unchanged, except what gravitation accomplishes in pulling down crater walls.
The law of universal gravitation was based on terrestrial and lunar observations, spectroscopic analysis was determined in a terrestrial laboratory.
There is a mutual attraction of gravitation between the earth and the moon.
It ascends from the surface of the earth or ocean laden with a stored energy, the power of which no man can compute, and beside which gravitation is a mere point.
The spectacle of a weight--for of course the hawk has an appreciable weight--apparently lifting itself in the face of gravitation and overcoming friction, is a very striking one.
It is necessary for him to "stroke" the air in order to keep up at all; because the moment he pauses gravitation exercises a force much greater than when he glides.
The attraction of gravitation decreases as distance increases, but the further away we are from Him, the stronger is the attraction which issues from Him, and would draw us to Himself.
To see an object rise from the earth by a law of Nature which seems to overcome gravitation to the sky while the string is yet in the hand, gives a boy a sense of power which excites his imagination and thrills his blood.
He who puts self under himself for the sake of justice has in him the gravitation of the skies.
Is it then at all mysterious, seeing that such is the case, that on the other particular of gravitation as well, she should differ from normal humanity?
But, her gravitationceasing the moment she left the water, away she went up into the air, scolding and screaming.
For the princess was a philosopher, and knew all the ins and outs of the laws of gravitation as well as the ins and outs of her boot-lace.
The water to be filtered is collected into large reservoirs, where subsidence by gravitation occurs.
The milk enters the lowest compartment by a pipe under gravitation pressure, and is forced upwards, and finally is run off into an iced cooler, and from that into the distribution cans.
An attack on the Newtonian mechanics; revolution by gravitation demonstrably impossible; much to be said for the earth being the immovable center.
What need to say anything to readers of Newton against a book from which I quoted that revolution by gravitation is demonstrably impossible?
The nonsense about Newton borrowing gravitation from Behmen passes only with those who know neither what Newton did, nor what was done before him.
The universities were what the monasteries had been under Charlemagne, the castles under Frederick Barbarossa,—the centres of gravitation for the intellectual and political life of the country.
After order had been restored by the first Hapsburg dynasty, the intellectual and literary activity of Germany retained its centre of gravitation in the middle classes.
And were the matter of the universe thrown in cold detached fragments into space, and there abandoned to the mutual gravitation of its own parts, the collision of the fragments would in the end produce the fires of the stars.
The law of gravitation enunciated by Newton is, that every particle of matter in the universe attracts every other particle with a force which diminishes as the square of the distance increases.
The idea of the attraction of gravitation was preceded by the observation of the attraction of iron by a magnet, and of light bodies by rubbed amber.
The principle of gravitation has been already described as an attraction which every particle of matter, however small, exerts on every other particle.
When the law of gravitation first suggested itself to the mind of Newton, what did he do?
Gravitation is a purely attractive force, but in electricity and magnetism, repulsion had been always seen to accompany attraction.
A dew-drop is not the less beautiful that it illustrates in its structure the law of gravitation which holds the world together, and by which "the most ancient heavens are fresh and strong.
During the ascending series the star is growing both in mass and heat, by the continual accretion of meteoritic matter either drawn to it by gravitation or falling towards it through the proper motions of independent masses.
But our mathematical astronomers can find no indications of such stability of the stellar universe as a whole, if subject to the law of gravitation alone.
Darwin sent my questions, writes:--'I doubt whether the principal phenomena of the stellar universe are consequences of the law of gravitation at all.
The disruption occurs from the well-known law of differential gravitation on the two sides of a body leading to tidal deformation in a liquid, and to unequal strain in a solid.
Newton's marvellous law of gravitation was coldly received even by the gigantic intellect of Leibnitz himself.
Compare this with the case of Newton, who similarly kept his grand idea of gravitation for many years in embryo, until more exact measurements of the moon's mass and distance should enable him to verify it to his own satisfaction.
Newton, again, had in due time been blamed in that he boldly substituted (as his critics declared) the bald and barren formula of gravitation for the personal superintendence of a divine Providence.
Newton substituted, for the old law of gravitation towards a centre, his law of universal gravitation, namely, that every particle gravitates towards every other.
The other theory of gravitation to which we call attention is that due to Le Sage of Geneva and published in 1818.
We now learn that conceptions of space of a highly unorthodox character are entertained by physicists and mathematicians, as the result of recent researches in the sphere of the gravitation of light.
And his work has the characteristic of permanency: his "gravitation formula" has stood the test of time.
