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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Page 92
... orbit at B , the force of projection would carry it to D , which brings it nearer the sun instead of bearing it away from it . Emily . If , then , we are driven by one power and drawn by the other to this centre of destruction , how is ...
... orbit at B , the force of projection would carry it to D , which brings it nearer the sun instead of bearing it away from it . Emily . If , then , we are driven by one power and drawn by the other to this centre of destruction , how is ...
Page 93
... orbit , is , in fig . 4. , divided into a number of areas , or spaces , 1 , 2 , 3 , 4 , & c . all of which are of equal dimensions , though of very different forms ; some of them , you see , are long and narrow , others broad and short ...
... orbit , is , in fig . 4. , divided into a number of areas , or spaces , 1 , 2 , 3 , 4 , & c . all of which are of equal dimensions , though of very different forms ; some of them , you see , are long and narrow , others broad and short ...
Page 94
... orbit , and how short they are in the other part ! Mrs. B. The inequality is not so considerable as appears in this figure ; for the earth's orbit is not so eccentric as it is there described ; and in reality , dif- fers but little from ...
... orbit , and how short they are in the other part ! Mrs. B. The inequality is not so considerable as appears in this figure ; for the earth's orbit is not so eccentric as it is there described ; and in reality , dif- fers but little from ...
Page 95
... orbit nearest the sun , it must have completed its journey through one half of its or- bit in a shorter time than the other half ? Mrs. B. Yes , it is about seven days ' longer perform- ing the summer - half of its orbit , than the ...
... orbit nearest the sun , it must have completed its journey through one half of its or- bit in a shorter time than the other half ? Mrs. B. Yes , it is about seven days ' longer perform- ing the summer - half of its orbit , than the ...
Page 97
... orbits more or less elliptical , according to the proportion which these two forces bear to each other . But the planets have also another motion : they re- volve upon their axis . The axis of a planet is an im- aginary line which ...
... orbits more or less elliptical , according to the proportion which these two forces bear to each other . But the planets have also another motion : they re- volve upon their axis . The axis of a planet is an im- aginary line which ...
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Common terms and phrases
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
Popular passages
Page 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...
Page 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.
Page 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...
Page 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.
Page 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...
Page 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.
Page 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...
Page 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.
Page 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.
Page 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.