Conversations on Natural Philosophy: In which the Elements of that Science are Familiarly Explained and Adapted to the Comprehension of Young Pupils : Illustrated with PlatesJ.Y. Humphreys, 1821 - 311 من الصفحات |
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الصفحة 31
... stone falls to the earth , the earth should rise part of the way to meet the stone ? Mrs. B. Certainly ; but you must recollect that the force of attraction is proportioned to the quantity of matter which bodies contain , and if you ...
... stone falls to the earth , the earth should rise part of the way to meet the stone ? Mrs. B. Certainly ; but you must recollect that the force of attraction is proportioned to the quantity of matter which bodies contain , and if you ...
الصفحة 44
... stone would put it in motion for ever . Mrs. B. The quantity of motion you communicate to the stone would not influence its duration ; if you threw it with little force it would move slowly , for its velocity , you must remember , will ...
... stone would put it in motion for ever . Mrs. B. The quantity of motion you communicate to the stone would not influence its duration ; if you threw it with little force it would move slowly , for its velocity , you must remember , will ...
الصفحة 45
... stone is thrown upwards , its velocity is gradually di- minished by the power of gravity . Mrs. B. Retarded motion is produced by some force acting upon the body in a direction opposite to that which first put it in motion : you who are ...
... stone is thrown upwards , its velocity is gradually di- minished by the power of gravity . Mrs. B. Retarded motion is produced by some force acting upon the body in a direction opposite to that which first put it in motion : you who are ...
الصفحة 46
... stone falling from a height moves with a regu- larly accelerated motion . Emily . True ; because the nearer it approaches the earth , the more it is attracted by it . Mrs. B. You have mistaken the cause of its accele- ration of motion ...
... stone falling from a height moves with a regu- larly accelerated motion . Emily . True ; because the nearer it approaches the earth , the more it is attracted by it . Mrs. B. You have mistaken the cause of its accele- ration of motion ...
الصفحة 47
... stone during the first instant of its descent , will continue in force every instant till it reaches the ground . Let us suppose that the impulse given by gra- vity to the stone during the first instant of its descent be equal to one ...
... stone during the first instant of its descent , will continue in force every instant till it reaches the ground . Let us suppose that the impulse given by gra- vity to the stone during the first instant of its descent be equal to one ...
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angle appear atmosphere attraction of cohesion axis ball called camera obscura Caroline centre of gravity centrifugal force circle coloured rays concave mirror consequently convergent convex mirror degrees descend diminishes direction distance diurnal motion divergent draw earth eclipse effect elastic Emily equal equator fixed stars fluid focus force fulcrum glass globe goblet greater heat heavier incident rays LENOX AND TILDEN lens less lever liquid mechanical power mercury meridian moon motion move nature nearer object observe orbit parallel rays particles pass perfectly perpendicular Philad planets plate pole pressure proceed produced proportion pulley pump quantity rays fall rays of light reflected rays refraction resistance retina rise round the sun shadow shine situated solid bodies space specific gravity sphere spout spring sun's rays supported suppose surface TILDEN FOUNDATIONS tion true tube understand vapour velocity vibrations weight whilst wind YORK PUBLIC LIBRARY
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الصفحة 102 - 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...
الصفحة 102 - The starry host, rode brightest, till the moon, Rising in clouded majesty, at length, Apparent queen, unveil'd her peerless light, And o'er the dark her silver mantle threw.
الصفحة 77 - ... 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...
الصفحة 216 - 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.
الصفحة 49 - B it receives in return a blow equal to that which it gave, but in a contrary direction, and its motion is thereby stopped, or rather, given to B. Therefore, when a body strikes against another, the quantity of motion communicated to the second body...
الصفحة 202 - ... the white rays of the sun are composed of coloured rays, which when blended together, appear colourless or white. Sir Isaac Newton, to whom we are indebted for the most important discoveries respecting light and colours, was the first who divided a white ray of light, and found it to consist of an assemblage of coloured rays, which formed an image upon the wall, such as is exhibited, in which are displayed the following series of colours — red, orange, yellow, green, blue, indigo, and violet.
الصفحة 64 - 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...
الصفحة 134 - I hope, thoroughly impressed upon your memory, by the conversation we have subsequently had on astronomy. It will now be necessary for me to give you some account of the mechanical properties of fluids, a science which is called hydrostaticS. A fluid is a substance which yields to the slightest pressure. If you dip your hand into a basin of water, you are scarcely sensible of meeting with any resistance.
الصفحة 117 - 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.
الصفحة 143 - All the metals expand by heat, and condense by cold. A piece of lead, let us say a cubic inch, for instance, would have less specific gravity in summer than in winter; for it would be more dense in the latter season. CAROLINE. • But, Mrs. B., if you compare the weight of equal quantities of different bodies, they will all be alike. You know the old saying, that a pound of feathers is as heavy as a pound of lead ! MRS.