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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Results 1-5 of 16
Page 42
... surrounded with an atmosphere which extends all round the earth , and above it to about the height of forty - five miles ; now the dotted part of Fig . 5. represents that atmosphere : suppose a spectator stand at s , and the sun 42 OPTICS .
... surrounded with an atmosphere which extends all round the earth , and above it to about the height of forty - five miles ; now the dotted part of Fig . 5. represents that atmosphere : suppose a spectator stand at s , and the sun 42 OPTICS .
Page 43
... spectator stand at s , and the sun to be at a ; if there were no refraction , the person at s would not see the rays of the sun till he were ཎྜ situate with regard to the sun in a line s ra ; because when it was be- low the horizon at b ...
... spectator stand at s , and the sun to be at a ; if there were no refraction , the person at s would not see the rays of the sun till he were ཎྜ situate with regard to the sun in a line s ra ; because when it was be- low the horizon at b ...
Page 45
... spectator will imagine he sees the sun in the line so n . Charles . What makes the moon look so much larger when it is just above the horizon , than when it is higher up ? Tutor . The thickness of the at- mosphere when the moon is near ...
... spectator will imagine he sees the sun in the line so n . Charles . What makes the moon look so much larger when it is just above the horizon , than when it is higher up ? Tutor . The thickness of the at- mosphere when the moon is near ...
Page 95
... spectator ; but the whole depends on the light of the sun for their beauty , to which the poet re- fers : - But see , the flush'd horizon flames intense With vivid red , in rich profusion stream'd O'er heaven's pure arch . At once the ...
... spectator ; but the whole depends on the light of the sun for their beauty , to which the poet re- fers : - But see , the flush'd horizon flames intense With vivid red , in rich profusion stream'd O'er heaven's pure arch . At once the ...
Page 125
... C D ( Plate III . Fig . 19. ) represents a convex mirror standing at the end of a room , before which the arrow A B is placed on one 豐 side or obliquely : where must the spectator stand to M 3 OF CONVEX MIRRORS . 125.
... C D ( Plate III . Fig . 19. ) represents a convex mirror standing at the end of a room , before which the arrow A B is placed on one 豐 side or obliquely : where must the spectator stand to M 3 OF CONVEX MIRRORS . 125.
Common terms and phrases
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
Popular passages
Page 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.
Page 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...
Page 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.
Page 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.
Page 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.
Page 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...
Page 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.
Page 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.
Page 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...