Conversations on Natural Philosophy: In which the Elements of that Science are Familiarly Explained, and Adapted to the Comprehension of Young Pupils. Illustrated with Plates

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Lincoln & Edmands, 1829 - 252 páginas
 

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Página 93 - Silence accompanied ; for beast and bird, They to their grassy couch, these to their nests, Were slunk, all but the wakeful nightingale ; She all night long her amorous descant sung ; Silence was pleased : now...
Página 93 - Now came still evening on, and twilight gray Had in her sober livery all things clad ; Silence accompanied ; for beast and bird, They to their grassy couch, these to their nests Were slunk, all but the wakeful nightingale ; She all night long her amorous descant sung...
Página 97 - Their names are Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricornus, Aquarius, Pisces; the whole occupying a complete circle, or broad belt., in the heavens, called the zodiack.
Página 72 - ... time that the axle describes a small one, therefore the power is increased in the same proportion as the circumference of the wheel is greater than that of the axle. If the...
Página 65 - I now perceive that the point at which the two levers are screwed together, is the fulcrum; the handles, to which the power of the fingers is applied, are the extremities of the acting part of the levers, and the cutting part of the scissors are the resisting parts of the levers ; therefore, the longer the handles, and the shorter the points of the scissors, the more easily will they cut.
Página 89 - THE planets are distinguished into primary and secondary. Those which revolve immediately about the sun are called primary. Many of these are attended in their course by smaller planets, which revolve round them : these are called secondary planets, satellites, or moons. Such is our moon which accompanies the earth, and is carried with it round the sun. Emily. How then can you reconcile the motion of the secondary planets to the laws of gravitation ; for the sun is much larger than any of the primary...
Página 223 - The flowers, in the same manner, reflect the various colours of which they appear to us; the rose, the red rays; the violet, the blue; the jonquil, the yellow, &c. Caroline. But these are the permanent colours of the grass and flowers, whether the sun's rays shine on them or not. Mrs. B. Whenever you see those colours, the flowers must be...
Página 112 - We shall now explain the variation of the seasons, and the difference of the length of the days and nights in those seasons — both effects resulting from the same cause.
Página 234 - This is to place a concave lens before the eye, in order to increase the divergence of the rays, the effect of a concave lens being exactly the reverse of a convex one. By the assistance of such glasses, therefore, the rays from a distant object fall on the pupil as divergent as those from a less distant object ; and, with short-sighted people they throw the image of a distant object back as far as the retina. Those who suffer from the...
Página 126 - ... full. As she proceeds in her orbit she becomes again gibbous, and her enlightened hemisphere turns gradually away from us till she completes her orbit and disappears, and then again resumes her form of a new moon. When the moon is...

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