Popular Lectures on Science and Art: Delivered in the Principal Cities and Towns of the United States, כרך 1Greeley & McElrath, 1846 |
מהדורות אחרות - הצג הכל
מונחים וביטויים נפוצים
acid alkali apparent magnitude appear Arago ascertained astronomical atmosphere attraction barometer body cause centre circumstances clouds color comet conductor consequently degree diameter direction discovery disk distance diurnal motion earth eclipse effect electricity electrified equal experiments fact fluid force glass globe greater Halley's comet heat height hemisphere Herschel hundred inch increased interval John Herschel Jupiter LECTURE less Leyden jar light liquid luminous lunar lunar phases magnitude mercury metallic meteors millions of miles motion move nature negative object observed orbit pass phenomena physical pile planet pole position present principle produced proportion quantity radiation rays reflected rendered round the sun Saturn seen Sir William Herschel solar solar eclipse solar system space stars substances sun's supposed surface telescope temperature theory thermometer thunder tides tion tricity tube vapor velocity vessel visible Voltaic Voltaic pile weather wire zenith zinc
קטעים בולטים
עמוד 121 - I say, if these things are so, may not the knowledge of this power of points be of use to mankind, in preserving houses, churches, ships, &c., from the stroke of lightning, by directing us to fix, on the highest parts of those edifices, upright rods of iron made sharp as a needle, and gilt to prevent rusting, and from the foot of those rods a wire down the outside of the building into the ground, or down round one of the shrouds of a ship, and down her side till it reaches the water?
עמוד 121 - If any danger to the man should be apprehended (though I think there would be none), let him stand on the floor of his box, and now and then bring near to the rod the loop of a wire that has one end fastened to the leads, he holding it by a wax handle ; so the sparks, if the rod is electrified, will strike from the rod to the wire, and not affect him.
עמוד 121 - To determine the question, whether the clouds that contain lightning are electrified or not, I would propose an experiment to be tried where it may be done conveniently.
עמוד 25 - The square of the hypotenuse of a right-angled triangle is equal to the sum of the squares of the other two sides.
עמוד 122 - With this apparatus, on the appearance of a thunder-gust approaching, he went out into the commons, accompanied by his son," to whom alone he communicated his intentions, well knowing the ridicule which, too generally for the interest of science, awaits unsuccessful experiments in philosophy.
עמוד 248 - Saturn, yet micrometrical measurements of extreme delicacy" have demonstrated that the coincidence is not mathematically exact, but that the centre of gravity of the rings oscillates round that of the body, describing a very minute orbit, probably under laws of much complexity.
עמוד 114 - Electricity, which was more generally read and admired in all parts of Europe than these letters. There is hardly any European language into which they have not been translated...
עמוד 121 - ... feet, pointed very sharp at the end. If the electrical stand be kept clean and dry, a man standing on it, when such clouds are passing low, might be electrified and afford sparks, the rod drawing fire to him from a cloud.
עמוד 171 - ... domain of physical science, and clothes the natural philosopher with powers denied to the political and moral inquirer, yet foreknowledge is eminently the privilege of the astronomer. Nature has raised the curtain of futurity, and displayed before him the succession of her decrees, so far as they...