A System of Natural Philosophy: In which the Principles of Mechanics, Hydrostatics, Hydraulics, Pneumatics, Acoustics, Optics, Astronomy, Electricity, and Magnetism, are Familiarly Explained, and Illustrated by More Than Two Hundred Engravings : to which are Added Questions for the Examination of the Pupils : Designed for the Use of Schools and Academies |
From inside the book
Results 1-5 of 22
Page viii
... Convex mirror , Concave mirror , Principal focus , Refraction by lenses , 152 Telescope , 161 Reflecting telescope ... lens , 169 Camera obscura , Magic lantern , 190 192 Concave lens , 172 Chromatics , 193 Vision , Eye , Spectacles ...
... Convex mirror , Concave mirror , Principal focus , Refraction by lenses , 152 Telescope , 161 Reflecting telescope ... lens , 169 Camera obscura , Magic lantern , 190 192 Concave lens , 172 Chromatics , 193 Vision , Eye , Spectacles ...
Page 168
... lens , when their axes coincide with the axes of the lens otherwise they are said to fall obliquely . The point at ... convex surfaces opposite to each other . A plano - concave lens , e , is bounded by a convex surface on one side , and ...
... lens , when their axes coincide with the axes of the lens otherwise they are said to fall obliquely . The point at ... convex surfaces opposite to each other . A plano - concave lens , e , is bounded by a convex surface on one side , and ...
Page 169
... Convex lens . It has been shown in a former part of this article , that when a ray of light passes obliquely out of ... convex lenses , depend on their de grees of convexity . The focal distance of a single , or plano- convex lens , is ...
... Convex lens . It has been shown in a former part of this article , that when a ray of light passes obliquely out of ... convex lenses , depend on their de grees of convexity . The focal distance of a single , or plano- convex lens , is ...
Page 170
... convex lens , d c , fig 151 , is that of two plano convex lenses , placed with their plane surfaces contact , and consequently the focal distance of this lens is nearly the centre of the sphere of which one of its surfaces is a part ...
... convex lens , d c , fig 151 , is that of two plano convex lenses , placed with their plane surfaces contact , and consequently the focal distance of this lens is nearly the centre of the sphere of which one of its surfaces is a part ...
Page 171
... lens , and are therefore brought to a focus near- er the lens , in proportion to their previous convergency . The eye glasses of spectacles . for old people are double convex lenses , more or less spherical , according to the age of the ...
... lens , and are therefore brought to a focus near- er the lens , in proportion to their previous convergency . The eye glasses of spectacles . for old people are double convex lenses , more or less spherical , according to the age of the ...
Common terms and phrases
air pump angle appear atmosphere attraction axis balance ball barometer barrel boat bulk called centre of gravity centrifugal force circle colors common concave mirror consequence convex lens convex mirror degrees descend diameter direction distance earth eclipse elastic electric equal equator exactly Explain fig falling body feet filled fluid fulcrum glass greater heat hence hydrometer illustrated inches inclined plane increased instrument kind of lever length lens less machine magnetic mercury meridian metals miles moon motion move object obliquely orifice particles pass pendulum perpendicular piece pipe piston poles pounds pressure principle proportion pulley quantity of matter raised rays of light reflected reflecting telescope refracted respect retina revolution revolve rise rope round screw seen side space specific gravity stars substances sun's Suppose surface suspended telescope thrown tion tube turned upwards valve velocity vessel vibrations visual angle weight
Popular passages
Page iv - In conformity to the act of Congress of the United States, entitled, " An act for the encouragement of learning, by securing the copies of maps, charts and books, to the authors and proprietors of such copies, during the times therein mentioned ;
Page iv - BBOWN, of the said district, hath deposited in this office the title of a book, the right whereof he claims as author, in the words following, to wit : " Sertorius : or, the Roman Patriot.
Page 128 - ... proceeding, when the captain's order came to prepare with all haste for a storm. The barometer had begun to fall with appalling rapidity. As yet, the oldest sailors had not perceived even a threatening in the sky, and were surprised at the extent and hurry of the preparations: but the required measures were not completed, when a more awful hurricane burst upon them than the most experienced had ever braved.
Page 236 - ... by which it is illustrated, that the sun constantly shines on a portion of the earth equal to 90 degrees north, and 90 degrees south from his place in the heavens, and consequently, that he always enlightens 180 degrees, or one half of the earth. If, therefore, the axis of the earth were perpendicular to the plane of its orbit, the days and nights would...
Page 232 - It has already been explained, that the ecliptic is the plane of the earth's orbit, and is supposed to be placed on a level with the earth's horizon, and hence, that this plane is considered the standard, by which...
Page 128 - ... hurricane burst upon them than the most experienced had ever braved. Nothing could withstand it; the sails already furled and closely bound to the yards, were riven away in tatters; even the bare yards and masts were in great part disabled; and at one time the whole rigging had nearly fallen by the board.
Page 18 - The intensity of light is found to increase and diminish in the same proportion. '^Thus, if a board a foot square, be placed at the distance of one foot from a candle, it will be found to hide the light from another board of two feet square, at the distance of two feet from the candle.
Page 290 - By connecting together a sufficient number of these jars, any quantity of the electric fluid may be accumulated. For this purpose all the interior coatings of the jars are made to communicate with each other, by metallic rods passing between them, and finally terminating in a single rod. A similar union is also established, by connecting the external coats with each other. When thus arranged, the whole series may be charged, as if they formed but one jar, and the whole series may be discharged at...
Page 215 - Different opinions have been entertained by astronomers respecting the cause of these belts and spots. By some they have been regarded as clouds, or as openings in the atmosphere of the planet, while...
Page 285 - The friction of the rubber against the glass plate (or cylinder) produces a transfer of the electric fluid from the rubber to the plate ; that is, the cushion becomes negatively and the glass positively electrified. The fluid which thus adheres to the glass, is carried round by the revolution of the cylinder ; and its escape being prevented by the silk...