Popular Lectures on Science and Art: Delivered in the Principal Cities and Towns of the United States, Τόμος 1Greeley & McElrath, 1846 |
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Συχνά εμφανιζόμενοι όροι και φράσεις
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 dogstar earth eclipse effect electricity electrified equal experiments fact fluid force full moon glass globe greater Halley's comet heat height hemisphere Herschel hundred inch increased interval John Herschel Jupiter less Leyden jar light liquid luminous lunar lunar phases magnitude matter 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 system space stars substances sun's supposed supposition surface telescope temperature theory thermometer thunder tides tion tricity tube vapor velocity vessel visible Voltaic Voltaic pile weather wire zinc
Δημοφιλή αποσπάσματα
Σελίδα 117 - 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.
Σελίδα 21 - The square of the hypotenuse of a right-angled triangle is equal to the sum of the squares of the other two sides.
Σελίδα 117 - ... 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? Would not these pointed rods probably draw the electrical fire silently out of a cloud before it came nigh enough to strike, and thereby secure us from that most sudden and terrible mischief?
Σελίδα 117 - The horizontal motion of the scales over the floor, may represent the motion of the clouds over the earth ; and the erect iron punch, a hill or high building ; and then we see how electrified clouds passing over hills or high buildings at too great a height to strike, may be attracted lower till within their striking distance. And, lastly, if a needle fixed on the punch with its point upright, or even on the floor below the punch, will draw the fire from the scale silently at a much greater than...
Σελίδα 116 - Take a pair of large brass scales, of two or more feet beam, the cords of the scales being silk. Suspend the beam by a packthread from the ceiling, so that the bottom of the scales may be about a foot from the floor; the scales will move round in a circle by the untwisting of the packthread. Set the iron punch on the end upon the floor, in such a place as that the scales may pass over it in making their circle ; then electrify one scale by applying the wire of a charged phial to it. As they move...
Σελίδα 118 - 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.
Σελίδα 244 - 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.
Σελίδα 110 - 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...
Σελίδα 117 - ... 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.
Σελίδα 167 - ... 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...