Elements of Natural Philosophy: Embracing the General Principles of Mechanics, Hydrostatics, Hydraulics, Pneumatics, Acopustics, Optics, Electricity, Galvanism, Magnetism, and Astronomy-- |
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angle appear astronomers atmosphere attraction axis ball called celestial centre of gravity circle colours comet concave constellations convex convex lens copper cylinder Define Describe diameter direction distance diurnal motion Earth eclipse effect electricity equal equator equinox experiment fall feet figure fixed stars fluid focus force Give the illustration glass globe heavenly bodies heavens hence Herschel horizon inches inclined plane instrument Jupiter length lens lever liquid luminous lunar eclipse machine magnet means Mercury meridian metal miles mirror Moon motion move object oblique Observation opposite orbit passing perpendicular pipes piston planet pole position pressure produced pulley rays of light reflected reflecting telescope refraction represented retina revolution revolve rise screw seen side solar solar eclipse space specific gravity Sun's supposed surface telescope tides tion tube valve velocity Venus vessel vibrations weight wheel wire wood-cut zinc
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Page 235 - Equal or mean time, is that which is reckoned by a clock, supposed to indicate exactly 24 hours, from 12 o'clock on one day to 12 o'clock on the next day. Apparent time, is that, which is measured by the apparent motion of the Sun in the heavens, as indicated by a meridian line, or sundial.
Page 242 - From these and other circumstances, many eminent astronomers are of opinion, that these four planets are the fragments of a large celestial body which once revolved between Mars and Jupiter, and which burst asunder by some tremendous convulsion, or some external violence. The discovery of Ceres by Piazzi, on the first day of the present century, drew
Page 55 - but such a force is much too great for the strength of any material with which we are acquainted. A small quantity of water, extending to a great elevation would give the pressure above described, it being only for the sake of convenience, that the forcing-pump is employed, instead of a column of water.
Page 57 - ounces. The weight which a body loses in a fluid, is to its whole weight as the specific gravity of the fluid is to that of the body. If a guinea weigh in air 129 grains, and
Page 110 - and the force of the heat at the focus is to the common heat of the sun, as the area of the glass is to the area of the focus. Illustration. If a lens four inches in diameter collect the
Page 30 - The broader the base, and the nearer the line of direction is to the centre of it, the more firmly does a body stand ; and the narrower the base of a body, and the nearer the line of direction is to the side of it, the more easily it is overthrown.
Page 79 - in motion by the impact of the water on the boards as they successively dip into it. As a wheel of this kind will revolve in any stream which furnishes a current of sufficient power, it may be used where the descent of the water is by far too trifling to turn a
Page 110 - If a lens four inches in diameter collect the sun's rays into a focus at the distance of twelve inches^ the image will not be more than onetenth of an inch in diameter ; the surface of this little circle is 1600 times
Page 178 - A circle is a plane figure bounded by a curved line, called the circumference, every part of which is equally distant from the centre.
Page 127 - and the retina. It has two fluids confined within these membranes, called the aqueous, and the vitreous humours, and one lens, called the crystalline. The sclerotic coat is the outer and strongest membrane, and its anterior part is well known as the •white of the eye. This coat is marked in the