Popular Lectures on Science and Art: Delivered in the Principal Cities and Towns of the United States, Volume 1

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Page 91 - ... 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?
Page 107 - 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.
Page 25 - The square of the hypotenuse of a right-angled triangle is equal to the sum of the squares of the other two sides.
Page 107 - 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...
Page 116 - ... animalcule. But how nobly is the darkness which envelopes metaphysical inquiries compensated by the flood of light which is shed upon the physical creation ! There all is harmony, and order, and majesty, and beauty. From the chaos of social and political phenomena exhibited in human records — phenomena unconnected to our imperfect vision by any discoverable law, a war...
Page 108 - 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.
Page 116 - ... with which whatever we are accustomed to call sublimity on our planet, dwindles into ridiculous insignificancy. Most justly has it been said, that nature has implanted in our bosoms a craving after the discovery of truth, and assuredly that glorious instinct is never more irresistibly awakened than when our notice is directed to what is going on in the heavens.
Page 170 - 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.
Page 100 - 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...
Page 91 - ... 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.

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