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
Արդյունքներ 24–ի 1-ից 5-ը:
Էջ 9
... that comes from the landscape , which I view by look- ing through the small hole in the paper , must come in all directions at the same time . - Take another in- stance ; if a candle be placed on an eminence THE MOTION OF LIGHT . 59.
... that comes from the landscape , which I view by look- ing through the small hole in the paper , must come in all directions at the same time . - Take another in- stance ; if a candle be placed on an eminence THE MOTION OF LIGHT . 59.
Էջ 11
... always moves in straight lines . James . How is that known ? Tutor . Look through a straight tube at any object , and the rays of light will flow readily from it to the eye , but let the tube be bent , and THE INTENSITY OF LIGHT .
... always moves in straight lines . James . How is that known ? Tutor . Look through a straight tube at any object , and the rays of light will flow readily from it to the eye , but let the tube be bent , and THE INTENSITY OF LIGHT .
Էջ 21
... look- ing - glass . You see yourselves , and one another also ; for the rays of light flow from you to the glass , and are reflected back again in the same lines . Now both of you stand on t one side of the room . What do you see ...
... look- ing - glass . You see yourselves , and one another also ; for the rays of light flow from you to the glass , and are reflected back again in the same lines . Now both of you stand on t one side of the room . What do you see ...
Էջ 29
... the sight of the mo- ney from me . Tutor . I will pour in a pitcher of clear water . James . I now see the shilling : how is this to be explained ? Tutor . Look to the last figure , ' and D3 THE REFLECTION OF LIGHT . 29.
... the sight of the mo- ney from me . Tutor . I will pour in a pitcher of clear water . James . I now see the shilling : how is this to be explained ? Tutor . Look to the last figure , ' and D3 THE REFLECTION OF LIGHT . 29.
Էջ 30
... Look to the last figure , ' and conceive your eye to be at s , a b the side of the pan , and the piece of money to be at r : now when the pan is empty , the rays of light flow from r , in the direction tam , but your eye is at s , of ...
... Look to the last figure , ' and conceive your eye to be at s , a b the side of the pan , and the piece of money to be at r : now when the pan is empty , the rays of light flow from r , in the direction tam , but your eye is at s , of ...
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
Սիրված հատվածներ
Էջ 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.
Էջ 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...
Էջ 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.
Էջ 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.
Էջ 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.
Էջ 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...
Էջ 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.
Էջ 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.
Էջ 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...