Scientific Dialogues: Intended for the Instruction and Entertainment of Young People, Inwich the First Principles of Natural and Experimental Philosophy are Fully Explained. Vol. II, IV-VI.J. Johnson, 1809 |
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Página 20
... meet . Charles . I see there are two an- gles , and they seem to be equal . Tutor . We cannot expect mathe- matical precision in such trials as these ; but if the experiment were accurately made , the two angles would be perfectly equal ...
... meet . Charles . I see there are two an- gles , and they seem to be equal . Tutor . We cannot expect mathe- matical precision in such trials as these ; but if the experiment were accurately made , the two angles would be perfectly equal ...
Página 48
... this figure represent ? Tutor . It represents a glass lens , of which there are several kinds . Parallel lines are those which being infi- nitely extended never meet . Charles . How do you describe a lens ? Tutor 48 . OPTICS . Y.
... this figure represent ? Tutor . It represents a glass lens , of which there are several kinds . Parallel lines are those which being infi- nitely extended never meet . Charles . How do you describe a lens ? Tutor 48 . OPTICS . Y.
Página 50
... meet in a certain point in that middle line . Tutor . That point c is called the focus : the dark part of this figure only represents the glass , as c d n . Charles . Have you drawn the cir cle to show the exact curve of the different ...
... meet in a certain point in that middle line . Tutor . That point c is called the focus : the dark part of this figure only represents the glass , as c d n . Charles . Have you drawn the cir cle to show the exact curve of the different ...
Página 51
... meet at a point behind it , the distance of which , from the middle of the glass , is exactly equal to the diameter of the sphere of which the lens is a portion . James . And in the case of a double conver , is the distance of the focus ...
... meet at a point behind it , the distance of which , from the middle of the glass , is exactly equal to the diameter of the sphere of which the lens is a portion . James . And in the case of a double conver , is the distance of the focus ...
Página 63
... meet in a point after they have passed through it ? Tutor . They will thus if the candle be placed at g , ( Plate II . Fig . 11. ) the rays , after passing the lens , will meet at r ; and this point a will be more or less distant from ...
... meet in a point after they have passed through it ? Tutor . They will thus if the candle be placed at g , ( Plate II . Fig . 11. ) the rays , after passing the lens , will meet at r ; and this point a will be more or less distant from ...
Termos e frases comuns
A B C A B Plate angle of incidence angle of reflection appear attract body called Charles colours compass concave lens concave mirror CONVERSATION convex lens convex mirror dark diameter direction distinct vision diverge double convex equal eye-glass farther feet figure flected focal distance focus of parallel formed half humours inches incident rays inverted image iron James ject lenses Let A B light flowing look looking-glass magnifying power means microscope move nearer needle nosegay object object-glass optic optic nerve painted parallel rays pass pencil of rays perpendicular piece plain mirror Plate 11 proceed radius rainbow rays fall rays flowing rays of light reflected rays reflecting telescope refraction retina seen shutter side small hole south pole spectator stance stand steel Suppose surface throw tion transparent tube Tutor violet vitreous humour
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Página 80 - Seasons return, but not to me returns Day, or the sweet approach of ev'n or morn, Or sight of vernal bloom, or summer's rose, Or flocks or herds or human face divine ; But cloud instead, and ever-during dark Surrounds me, from the cheerful ways of men Cut off, and for the book of knowledge fair Presented with an universal blank Of nature's works, to me expung'd and ras'd, And wisdom at one entrance quite shut out.
Página 85 - First the flaming red Sprung vivid forth ; the tawny orange next ; And next delicious yellow ; by whose side Fell the kind beams of all-refreshing green. Then the pure blue, that swells autumnal skies, Ethereal...
Página 8 - How distant some of these nocturnal suns ! So distant (says the sage) 'twere not absurd To doubt, if beams, set out at nature's birth, Are yet arriv'd at this so foreign world ; Though nothing half so rapid as their flight.
Página 109 - ... as the angle of reflection is always equal to the angle of incidence, the image for any point can be seen only in the reflected ray prolonged.
Página 166 - Meantime, refracted from yon eastern cloud, Bestriding earth, the grand ethereal bow Shoots up immense; and every hue unfolds, In fair proportion, running from the red To where the violet fades into the sky.
Página 172 - Died in the fainting Violet away. These, when the clouds distil the rosy shower, Shine out distinct adown the watery bow ; While o'er our heads the dewy vision bends Delightful, melting on the fields beneath. Myriads of mingling dyes from these result, And myriads still remain ; infinite source Of beauty, ever blushing, ever new. Did ever poet image aught so fair, Dreaming in whispering groves, by the hoarse brook; Or prophet, to whose rapture heaven descends...
Página 187 - Yes; the three glasses next the eye baving their focal distances equal, the magnifying power is found by dividing the focal distance of the object-glass by the focal distance of one of. the eye-glasses.
Página 49 - A lens is glass ground into such a form, as to collect or disperse the rays of light which pass through it. These are of different shapes, and from thence receive different names.
Página 61 - If anoto glass, FG, of the same convexity as DE, be placed in the rays at the same distance from the focus, it will refract them so, as that, after going out of it, they will be all parallel...