Hand-books of Natural Philosophy and Astronomy: Mechanics. Hydrostatics, hydraulics, pneumatics, and sound. Optics.- v. 2. Heat. Magnetism, common electricity, and voltaic electricity.- v. 3. Meteorology. AstronomyBlanchard and Lea, 1851 - Astronomy |
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Common terms and phrases
acting already explained angle of incidence angle of refraction applied atmosphere axis axle ball barometer body centre of gravity centrifugal force CHAP column compressed consequently cord cubic foot cylinder density depth determined diameter diminished direction distance effect elastic equal equilibrium example experiment expressed fall feet fluid focus friction glass glottis greater immersed imparted inclined plane increased index of refraction length less lever light liquid machine magnitude manner mass matter mercury metal momentum motion moving force nodal nodal lines number of vibrations object orifice oscillation parallel particles passing pendulum perpendicular piston placed plate position power and weight pressure principle produced proportion pulley quantity rarefaction rays reflected reflector refraction represented in fig resistance rest revolve rope round screw side solid sound space specific gravity spherical reflector square inch string suppose surface suspended tion transmitted tube undulations upwards velocity vessel waves wheel
Popular passages
Page 517 - When a ray of light passes from one medium to another, it is refracted so that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the velocities in the two media.
Page 89 - Every body must persevere in its state of rest, or of uniform motion in a straight line, unless it be compelled to change that state by forces impressed upon it." II. " Every change of motion must be proportional to the impressed force, and must be in the direction of that straight line in which the force is impressed.
Page 19 - ... of an ounce. But we need not stop even here. This portion of the wire may be viewed through a microscope which magnifies 500 times; and by these means, therefore, its 500th part will become visible.
Page 341 - Thus, if fair weather follow immediately the rise of the mercury, there will be very little of it, and, in the same way, if foul weather follow the fall of the mercury, it will last but a short time. (4.) If fair weather continue for several days, during which the mercury continually falls, a long succession of...
Page 341 - TLe following rules may to some extent be relied upon, but even these are subject to much uncertainty. 1. Generally the rising of the mercury indicates the approach of fair weather, the falling of it shows the approach of foul weather. 2. In sultry weather, the fall of the mercury indicates coming thunder. In winter the rise of the mercury indicates frost. In frost, its fall indicates thaw, and its rise indicates snow.
Page 203 - ... theory, viz., the friction which arises between its surface and the substance which it divides. This is the case when pins, bolts, or nails, are used for binding the parts of structures together ; in which case, were it not for the friction, they would recoil from their places, and fail to produce the desired effect. Even when the wedge is used as a mechanical engine, the presence of friction is absolutely indispensable to its practical utility. The power...
Page 204 - The power, as has already been stated, generally acts by successive blows, and is therefore subject to constant intermission, and, but for the friction, the wedge would recoil between the intervals of the blows with as much force as it had been driven forward.
Page 180 - The treddle of the turning lathe is a lever of the third kind. The hinge which attaches it to the floor is the fulcrum, the foot applied to it near the hinge is the power, and the crank upon the axis of the fly-wheel, with which its extremity is connected, is the weight. Tongs are levers of this kind, as also the shears Used in shearing sheep. In these cases the power is the hand placed immediately below the fulcrum or point where the two levers are connected.
Page 222 - Some engines used in coining have flies with arms four feet long, bearing one hundred weight at each of their extremities. By turning such an arm at the rate of one entire circumference in a second, the die will be driven against the metal with the same force as that with which 7500 pounds weight would fall from the height of 16 feet ; an enormous power, if the simplicity and compactness of the machine be considered.