A Dictionary of Chemistry and the Allied Branches of Other Sciences, Volume 5

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Longmans, Green, and Company, 1868 - Chemistry
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Page 394 - ... approaches the horizon. It does not, on the other hand, seem at all unlikely, owing to the high temperature which we must suppose the sun's atmosphere to possess, that such vapours should be present in it. Hence the observations of the solar spectrum appear to me to prove the presence of iron vapour in the solar atmosphere with as great a degree of certainty as we can attain in any question of natural science.
Page 362 - ... once what is the weight of a quantity of water, equal in bulk to the solid matter in the sand ; and by comparing this with the weight of the sand, we have its true specific gravity.
Page 363 - This result gives the weight of a bulk of water equal to that of the specimen, and by dividing the weight of the specimen in air by this number, the specific gravity is obtained.
Page 570 - It is sparingly soluble in water, but mixes in all proportions with alcohol and ether. It burns with difficulty...
Page 393 - that the same body when heated so as to become luminous must emit the precise rays which at ordinary temperatures are absorbed ; ' after which remarkable conjecture, now amply verified by experiment, he goes on to say, ' I am therefore convinced that the explanation of the dark lines in the solar spectrum embraces that of the luminous lines in the electric spectrum.
Page 401 - The colours of the stars have their origin in the chemical constitution of the atmospheres which surround them. 4. The changes in brightness of some of the variable stars are attended with changes in the lines of absorption of their spectra. 5. The phenomena of the star in Corona appear to show that in this object at least great physical changes are in operation.
Page 334 - Chalk 3 , These materials must be very intimately mixed by pounding and sifting, and it is advantageous to calcine the mixture before introducing it into the distilling apparatus, provided the calcination can be effected by the waste heat of a furnace ; the mixture is thereby rendered more compact, so that a much larger quantity can be introduced into a vessel of given size.
Page 394 - Hence this coincidence," says Kirchhoff, " must be produced by some cause ; and a cause can be assigned which affords a perfect explanation of the phenomenon. The observed phenomenon may be explained by the supposition that the rays of light which form the solar spectrum have passed through the vapour of iron, and have thus suffered the Absorption which the vapour of iron must exert.
Page 387 - The colours thus communicated by the different bases to flame afford, in many cases, a ready and neat way of detecting extremely minute Quantities of them...
Page 392 - In order to find out the extent to which the intensity of the solar spectrum could be increased, without impairing the distinctness of the sodium lines, I allowed the full sunlight to shine through the sodium flame upon the slit, and, to my astonishment, I saw that the dark lines D appeared with an extraordinary degree of clearness.

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