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 |
From inside the book
Results 1-5 of 13
Page 49
... concave ; and E is called a meniscus , being convex on one side , and con- cave on the other ; of this kind are all watch glasses . VOL . V. F James . I can easily conceive of diverging rays , OF THE DIFFERENT LENSES . 49.
... concave ; and E is called a meniscus , being convex on one side , and con- cave on the other ; of this kind are all watch glasses . VOL . V. F James . I can easily conceive of diverging rays , OF THE DIFFERENT LENSES . 49.
Page 51
... lenses ? Tutor . Yes : and you see that parallel rays falling upon a plano- convex ... lens is a portion . James . And in the case of a double conver , is the ... concave surfaces have double the effect in refracting rays to what a single ...
... lenses ? Tutor . Yes : and you see that parallel rays falling upon a plano- convex ... lens is a portion . James . And in the case of a double conver , is the ... concave surfaces have double the effect in refracting rays to what a single ...
Page 75
... lens , they will be collected at a point nearer to the lens than the focus of parallel rays . But if they diverge before they enter the lens , they will then be collected in a point beyond the focus of parallel rays . There are concave ...
... lens , they will be collected at a point nearer to the lens than the focus of parallel rays . But if they diverge before they enter the lens , they will then be collected in a point beyond the focus of parallel rays . There are concave ...
Page 76
... mn , and the ray e in the direction r s , and so on . The ray c x in the cen- tre suffers no refraction , but proceeds precisely as if no glass had been in the way . James . Suppose the lens had been concave only on 76 OPTICS .
... mn , and the ray e in the direction r s , and so on . The ray c x in the cen- tre suffers no refraction , but proceeds precisely as if no glass had been in the way . James . Suppose the lens had been concave only on 76 OPTICS .
Page 77
... lens had been concave only on one side , and the other side had been flat , how would the rays have diverged ? Tutor . They would have diverged after passing through it , as ... concave lens , or those formed by a H 3 OF CONCAVE LENSES . 77.
... lens had been concave only on one side , and the other side had been flat , how would the rays have diverged ? Tutor . They would have diverged after passing through it , as ... concave lens , or those formed by a H 3 OF CONCAVE LENSES . 77.
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...