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 Pupils : Designed for the Use of Schools and Academies |
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Page vi
... focus , Refraction by lenses , Various kinds of lenses , Convex lens , Concave lens , 162 Gregory's telescope , 189 167 Herschel's telescope , 190 168 Camera obseura , 190 169 Magic lantern , 192 172 Chromatics , 193 Vision , Eye ...
... focus , Refraction by lenses , Various kinds of lenses , Convex lens , Concave lens , 162 Gregory's telescope , 189 167 Herschel's telescope , 190 168 Camera obseura , 190 169 Magic lantern , 192 172 Chromatics , 193 Vision , Eye ...
Page vi
... focus , Refraction by lenses , Various kinds of lenses , Convex lens , Concave lens , Vision , Eye , Spectacles , Solar system , Ecliptic , Zodiac , Density of the planets , The sun , 121 Forcing pump , 123 Fire engine , 128 Fountain of ...
... focus , Refraction by lenses , Various kinds of lenses , Convex lens , Concave lens , Vision , Eye , Spectacles , Solar system , Ecliptic , Zodiac , Density of the planets , The sun , 121 Forcing pump , 123 Fire engine , 128 Fountain of ...
Page 160
... focus in a contrary direction , were they prolonged behind the mirror , so it cannot appear as far behind the reflecting sur- face as the object is before it , for the more widely the rays meeting at the eye are separated , the shorter ...
... focus in a contrary direction , were they prolonged behind the mirror , so it cannot appear as far behind the reflecting sur- face as the object is before it , for the more widely the rays meeting at the eye are separated , the shorter ...
Page 161
... focus . What is the shape of the concave mirror , and in what respect does it differ from the convex mirror ? How may convex and concave mirrors be united in the same instrument ? What is the difference of effect be- tween the concave ...
... focus . What is the shape of the concave mirror , and in what respect does it differ from the convex mirror ? How may convex and concave mirrors be united in the same instrument ? What is the difference of effect be- tween the concave ...
Page 162
... focus of the reflector . But if the incident rays are divergent , the focus will be re- moved to a greater distance from the surface of the mirror , than when they are parallel , in proportion to their divergency . This might be ...
... focus of the reflector . But if the incident rays are divergent , the focus will be re- moved to a greater distance from the surface of the mirror , than when they are parallel , in proportion to their divergency . This might be ...
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Common terms and phrases
appear atmosphere attraction axle ball barrel called centre of gravity centrifugal force circle colors concave mirror conductor consequently convergent convex lens convex mirror degrees diameter direction distance earth earth's orbit eclipse elastic electric fluid equal equator equinoxes Explain fig falling body feet fixed stars focus fulcrum glass heat hence illustrated inches inclined plane increased instrument length lenses less lever longitude machine magnetic mercury meridian metals millions of miles moon motion move Natural Philosophy object obliquely obvious particles pass pendulum perpendicular piston plane mirror planets poles pounds pressure principle proportion pulley pump quantity of matter raised rays of light reflected reflecting telescope refracted respect retina revolution revolve rope screw seen side solar space specific gravity substances sun and clock sun's Suppose surface telescope thrown tion tube turned velocity vessel visual angle weight wheel
Popular passages
Page ii - 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 time therein mentioned.
Page ii - 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 ii - ... 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,' and extending the benefits thereof to the arts of designing, engraving, and etching historical and other prints.'/ CHARLES A.
Page 207 - The circumference of every circle is supposed to be divided into 360 equal parts called degrees, and each degree into 60 equal parts called minutes, and each minute into 60 equal parts called seconds, and these into thirds, fourths, &c.
Page 238 - ... 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 12 - When a piece of wood is heated in a close vessel, such as a retort, we obtain water, an acid, several kinds of gas, and there remains a black, porous substance, called charcoal. The wood is thus decomposed or destroyed, and its particles take a new arrangement, and assume new forms ; but that nothing is lost, is proved by the fact, that if the water, acid...
Page 217 - 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 others imagine that they are of a more permanent...
Page 130 - 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. 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...
Page 266 - The ebbing and flowing of the sea, which regularly takes place twice in 24 hours, are called the tides. The cause of the tides, is the attraction of the sun and moon, but chiefly of the moon on the waters of the ocean. In virtue of the universal principle of gravitation...
Page 208 - Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces.