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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Страница 65
... b and a , and the rays from A must , for the same reason , be re- fracted to a . James . If the object A B C is brought nearer to the glass , will the picture be removed to a greater di- stance ? Tutor G 3 OF THE INVERTED IMAGE . 65.
... b and a , and the rays from A must , for the same reason , be re- fracted to a . James . If the object A B C is brought nearer to the glass , will the picture be removed to a greater di- stance ? Tutor G 3 OF THE INVERTED IMAGE . 65.
Страница 66
... brought nearer to the glass than F , then they will diverge from one another , so that in neither case an image will be formed behind the lens . James . To get an image , must the object be beyond the focus F ? Tutor . It must : and the ...
... brought nearer to the glass than F , then they will diverge from one another , so that in neither case an image will be formed behind the lens . James . To get an image , must the object be beyond the focus F ? Tutor . It must : and the ...
Страница 87
... to the separation of the different rays , that I saw the rainbow colours about the edges of the image made with the lens ? Tutor . It was : some of the rays were scattered , and not brought to a focus , 12 OF COLOURS . 87.
... to the separation of the different rays , that I saw the rainbow colours about the edges of the image made with the lens ? Tutor . It was : some of the rays were scattered , and not brought to a focus , 12 OF COLOURS . 87.
Страница 88
... brought to a focus , and these were divided in the course of refraction . And I may tell you now , though I shall not explain it at present , that the rainbow in the heavens is caused by the separation of the rays of light into their ...
... brought to a focus , and these were divided in the course of refraction . And I may tell you now , though I shall not explain it at present , that the rainbow in the heavens is caused by the separation of the rays of light into their ...
Страница 143
... never feel uneasy after sitting some time in the dark , when candles were suddenly brought into the room ? James . Yes : I remember last Friday evening we had been sitting half an hour almost in the dark at Mr. W OF THE EYE . 143.
... never feel uneasy after sitting some time in the dark , when candles were suddenly brought into the room ? James . Yes : I remember last Friday evening we had been sitting half an hour almost in the dark at Mr. W OF THE EYE . 143.
Често срещани думи и фрази
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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Страница 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.
Страница 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...
Страница 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.
Страница 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.
Страница 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.
Страница 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...
Страница 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.
Страница 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.
Страница 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...