Magazine of Popular Science, and Journal of the Useful Arts, 第 3 巻

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1837

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408 ページ - Resolved, that the Secretary of the Treasury be requested to report to the House at its next session upon the propriety of establishing a system of telegraphs for the United States.
85 ページ - Weigh the denser body and the compound mass, separately, both in water and out of it ; then find how much each loses in water, by subtracting its weight in water from its weight in air ; and subtract the less of these remainders from the greater. Then say, As the last remainder, Is to the weight of the light body in air, So is the specific gravity of water, To the specific gravity of the body.
261 ページ - Strapped obliquely across the shoulder of a horseman, however, it travels securely and well, and with common care in this mode of transport, its zero runs no risk of change. The next correction, and the most important of all, is that due to the temperature of the Mercury in the Barometer tube at the time of observation. To obtain this, every Barometer requires to have attached to, or fixed very near it, a Thermometer, called the attached Thermometer, which must be read and registered at each observation...
261 ページ - All these and the like corrections, being matter of calculation and reasoning from other observations, are to be reserved till the final discussion of the series, and for separate determination and statement. 5. If copies be taken of the registers, they should be carefully compared with the originals by two persons, one reading aloud from the original and the other attending to the copy, and then exchanging parts, a process always advisable wherever great masses of figures are required to be correctly...
261 ページ - Thermometer should be read off, and registered hourly, and the precise hour and minute of each reading should be especially noted. For obvious reasons, however, the commencement of every hour should, if practicable, be chosen, and every such series of observations should be accompanied by a notice of the means used to obtain the time, and, when practicable, by some observation of an astronomical nature, by which the time can be independently ascertained within a minute or...
104 ページ - Sun with a force directly as their mass and inversely as the square of their distance...
88 ページ - During the month of June last year (1836), in a course of lectures delivered at King's College, London, Professor Wheatstone repeated his experiments on the velocity of electricity which were published in the Philosophical Transactions...
261 ページ - ... 3. The observations should, if possible, all be made by one person ; but as this may often be impracticable, the principal observer should take care to instruct one or more of his family how to do it, and should satisfy himself by many trials that they observe alike. 4. The entries in the register should be made at the time of observation, and the numbers entered should be those actually read off on the respective scales of each instrument, on no account applying to them previous to entry any...
317 ページ - ... from the aspect of the heavens below that limit. It would be better to notice both, and state, separately, the proportions in which each are covered, and the quarter of the horizon towards which the chief masses in the lower region lie. The general aspect of Clouds, as classed under the heads Cumulus, Cirrus, Stratus, &c. should be noticed, and especially the height of this inferior surface, or the level of the vapour plane, should be estimated.
315 ページ - The best measure of the momentary evaporating power of the air seems to be the depression of the wetted thermometer below the dry one. But the actual evaporation from a given surface is quite another thing, and a question may very reasonably be raised, how far any useful approximation to a knowledge of the total evaporation from an extensive and diversified surface, unequally moistened, and variously exposed to the sun, defended by clouds, or refreshed by dews, can be obtained by any small or local...

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