Conversations on Natural Philosophy: In which the Elements of that Science are Familiarly Explained and Adapted to the Comprehension of Young PupilsLincoln & Edmands, 1829 - 252 страница |
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angle angle of incidence appear astronomy atmosphere axis ball called camera obscura Caroline centre of gravity centrifugal force circle cohesive attraction concave mirror consequently convex mirror degrees diminished direction distance diurnal motion earth eclipse ecliptick effect Emily equal equator explain figure fixed stars focus force fulcrum geometry glass globe greater heat humour lens less lever liquids mechanical power mechanicks mercury meridian moon motion move Natural Philosophy nature object obliquely observe opaque body opposite opticks orbit particles passes perpendicular planets plate poles pressure produced proportion pulley pump rays fall rays of light re-action reflected rays reflecting telescope refraction represents resistance retina revolve round right line rise round the sun shadow shines situated solar solid bodies sonorous body sound space specifick gravity sphere spring sun's rays suppose surface tides tion tube understand vapour velocity vibrations weight whilst wind zodiack
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Страница 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...
Страница 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...
Страница 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.
Страница 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...
Страница 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.
Страница 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...
Страница 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...
Страница 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.
Страница 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...
Страница 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...