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 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...

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