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 21
Page 229
... poles : to the former a mark is placed , for the purpose of distinguishing it . James . Then if a ship were to make a voyage to the north , it must follow the direction which the magnet takes . Tutor . True ; and if it were bound ...
... poles : to the former a mark is placed , for the purpose of distinguishing it . James . Then if a ship were to make a voyage to the north , it must follow the direction which the magnet takes . Tutor . True ; and if it were bound ...
Page 230
... pole star ? Tutor . It might , in a consider- able degree , provided you could al- ways ensure a fine clear sky ; but what is to be done in cloudy wea- ther , which , in some latitudes , will last for many days together ? Charles . I ...
... pole star ? Tutor . It might , in a consider- able degree , provided you could al- ways ensure a fine clear sky ; but what is to be done in cloudy wea- ther , which , in some latitudes , will last for many days together ? Charles . I ...
Page 232
... pole this is called the polarity of the magnet . ( 3. ) When the north pole of one magnet is presented to the south pole of another , they will attract one another . But if the two south , or the two north poles , are pre- sented to ...
... pole this is called the polarity of the magnet . ( 3. ) When the north pole of one magnet is presented to the south pole of another , they will attract one another . But if the two south , or the two north poles , are pre- sented to ...
Page 233
... poles of it do not lie in an horiontal direction , it inclines one of it poles towards the horizon , and , of ourse , elevates the other pole above it ; this is called the inclina- tion or dipping of the magnet . ( 5. ) Ary magnt may be ...
... poles of it do not lie in an horiontal direction , it inclines one of it poles towards the horizon , and , of ourse , elevates the other pole above it ; this is called the inclina- tion or dipping of the magnet . ( 5. ) Ary magnt may be ...
Page 235
... poles , so that in the middle , between the poles , there is no attraction , as you shall see by means of this large needle . 34 James When you held the needle near the pole of the magnet , the magnet moved to that , which looks as if ...
... poles , so that in the middle , between the poles , there is no attraction , as you shall see by means of this large needle . 34 James When you held the needle near the pole of the magnet , the magnet moved to that , which looks as if ...
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...