What to Observe: Or, The Traveller's Remembrancer

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J. Madden & Company, 1841 - Scientific expeditions - 577 pages

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Page 91 - Sometimes this and the Cirro-cumulus appear together in the sky, and even alternate with each other in the same cloud; when the different evolutions which ensue...
Page 108 - ... 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...
Page 86 - The usual course of periodical winds, or such as remarkably prevail during certain seasons, with the law of their diurnal progress, both as to direction and intensity ; at what hours, and by what degrees they commence, attain their maximum, and subside ; and through what points of the compass they run in so doing.
Page 90 - The Rain cloud. A cloud, or system of clouds from which rain is falling. It is a horizontal sheet, above which the Cirrus spreads, while the Cumulus enters it laterally and from beneath.
Page 463 - A. A common tin pot, 9 inches high by 2 in diameter. B. A sliding tube of tin, moving up and down in the pot : the head of the tube is closed, but has a slit in it, C, to admit of the thermometer passing through a collar of cork, which shuts up the slit where the thermometer is placed. D. Thermometer, with as much of the scale left out as may be desirable.
Page 91 - On the return of the sun, the level surface of this cloud begins to put on the appearance of cumulus, the whole at the same time separating from the ground. The continuity is next destroyed, and the cloud ascends and evaporates, or passes off with the appearance of the nascent cumulus.
Page 539 - ... above the bottom of the pot. Violent ebullition was continued for ten minutes or a quarter of an hour, and the height of the mercury was repeatedly ascertained during that time, and the temperature of the air was noticed. Similar operations were repeated with a second thermometer, for it is never safe to rely upon one instrument.
Page 543 - When the boiling point at the upper station alone is observed, and for the lower the level of the sea or the register of a distinct barometer is taken, then the barometric reading had better be converted into feet, by the usual method of subtracting its logarithm from 1•47712 (log. of 30 inches) and multiplying by '0006, as the differences in the column of " barometer" vary more rapidly than those in the "feet
Page 108 - 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...
Page 168 - Iron, is met with in four different mineral eras, but in different ores. Among primitive rocks, magnetic iron ore and specular iron ore occur chiefly in beds, sometimes of enormous size; the ores of red or brown oxide of iron...

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