Elements of natural philosophy

Przednia okładka
1839 - 120

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Strona xxx - The qualities of bodies, which admit neither intension nor remission of degrees, and which are found to belong to all bodies within the reach of our experiments, are to be esteemed the universal qualities of all bodies whatsoever.
Strona 363 - Brewster*, with a happy sagacity, discovered the formula to be simply this, that the index of refraction is the tangent of the angle of polarization.
Strona 123 - Impenetrability, — which signifies that no two bodies can occupy the same space at the same time.
Strona 126 - ... of the whole quantity of matter in the earth. But the attraction of a quantity of matter at the earth's centre would be more powerful on a body at the bottom of a mine than on one at the top, in the inverse ratio of the squares of the distances of the bodies from the earth's centre : that is in the present case in the ratio of four to one. Hence the attraction on a body at the bottom of the mine would be, on the whole, less than the attraction on a body on the top in the ratio of one to two.
Strona xxx - In experimental philosophy we are to look upon propositions inferred by general induction from phenomena as accurately or very nearly true, notwithstanding any contrary hypotheses that may be imagined, till such time as other phenomena occur, by which they may either be made more accurate, or liable to exceptions.
Strona 90 - ... by the solid. Hence we obtain what is called the principle of Archimedes, namely, that a body immersed either wholly or partially in a fluid loses a portion of its weight equal to that of the fluid which it displaces. This principle is of great importance as regards the flotation of bodies, and the determination of specific gravity, etc.
Strona 399 - If we hold a slip of white paper vertically, about a foot from the eye, and direct both eyes to an object at some distance beyond it, so as to see the slip of paper double, then, when a candle is brought near the right eye, so as to act strongly upon it, while the left eye is protected from its light, the...
Strona 37 - The disciples of Plato contributed not a little to the advancement of optics, by the important discovery they made, that light emits itself in straight lines, and that the angle of incidence is always equal to the angle of reflection. Plato terms colours " the effect of light transmitted from bodies, the small particles of which were adapted to the organ of sight.
Strona xxvii - ... exposed to every variety of attack which splendid talents quickened into energy by the keen perception of personal interests can suggest, — when they have revived undying from unmerited neglect ; when the anathema of spiritual, and the arm of secular power have been found as impotent in suppressing, as their arguments were in refuting them, then they are indeed irresistible. Thus tried and thus triumphant in the fiercest warfare of intellectual strife, even the temporary interests and furious...
Strona 112 - The velocity of fluids thus escaping from orifices, is, ctsteris paribus, as the square roots of the depths of the orifices below the surface of the fluid. Thus calling the velocity of a fluid, escaping from an orifice one foot below the surface, unity : the velocity of a fluid, escaping from a similar orifice 4 feet below the level, will be 2 ; at 9 feet 3 ; at 16 feet 4, and so on. 197- When fluids escape from lateral apertures, they describe parabolic curves, and obey the laws of projectiles (93)...

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