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
George Goodwin & sons, 1821 - 311 páginas
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angle appear atmosphere attraction axis ball body called Caroline centre centre of gravity Certainly circle color consequently consider contain course dark described diminishes direction distance draw earth effect elastic Emily equal equator exactly experiment explain fall figure fixed fluid focus force give glass globe gravity greater heat heavy hour idea increased latter length lens less lever light means mechanical meet mirror moon motion move nature never object obliquely observe opposite orbit particles passes perfectly perpendicularly planets plate pole pressure proceed produced projection properties proportion pump quantity raise rays rays of light reach reason receiver reflected refraction represents resistance retina rise round shadow shine side situated sound space stars string sun's supported suppose surface tion true understand velocity vibrations weight whilst whole wind
Página 126 - ... 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; Silence was pleased: now...
Página 140 - evidence of things not seen," in the fulness of Divine grace ; and was profound on this, the greatest concern of human life, while unable even to comprehend how the " inclination of the earth's axis to the plane of its orbit" could be the cause of the change of the seasons.
Página 125 - 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 98 - ... 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 291 - The construction of the eye is so admirable, that it is capable of adapting itself, more or less, to the circumstances in which it is placed. In a faint light the pupil dilates so as to receive an additional quantity of rays, and in a strong light it contracts, in order to prevent the intensity of the light from injuring the optic nerve.
Página 103 - When, therefore, the surfaces of the two bodies come into contact, the prominent parts of the one will often fall into the hollow parts of the other, and occasion more or less resistance to motion. In proportion as the surfaces of bodies are well polished, the friction is diminished; but it is always considerable, and it is usually computed to destroy one-third of the power of a machine.
Página 43 - ... regions. The pressure of the atmosphere has been compared to that of a pile of fleeces of wool, in which the lower fleeces are pressed together by the weight of those above : these lie light and loose, in proportion as they approach the uppermost fleece, which receives no external pressure, and is confined merely by the force of its own gravity.
Página 76 - The curve-line which the ball has described, is called in geometry, a parabola; but when the ball is thrown perpendicularly upwards, it will descend perpendicularly ; because the force of projection, and that of gravity, are in the same line of direction. We have noticed the centres of magnitude, and of motion ; but I have not yet explained to you what is meant by the centre of gravity ; it is that point in a body, about which all the parts exactly balance each other ; if, therefore, that point is...
Página 294 - 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.
Página 301 - XY (fig. 2.) in it, to converge the rays to a focus on the object A B. There is but one thing more wanting to complete .the solar microscope, which I shall leave to Caroline's sagacity to discover. CAROLINE. Our microscope has a small mirror attached to it, upon a moveable joint, which can be so adjusted as to receive the sun's rays, and reflect them upon the object. If a similar mirror were placed to reflect light upon the lens, would it not be a means of illuminating the object more perfectly?...