Proceedings of the Royal Society of London

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Taylor & Francis, 1874 - Science


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Page 12 - The PRESIDENT then delivered his Address, (p. 65.) It was proposed by Mr. LATHAM, seconded by Mr. FIELD, and resolved:— " That the thanks of the Society be given to the President for his Address, and that he be requested to allow it to be printed in the Quarterly Journal of the Society.
Page 146 - I look at the geological record as a history of the world imperfectly kept, and written in a changing dialect ; of this history we possess the last volume alone, relating only to two or three countries. Of this volume, only here and there a short chapter has been preserved ; and of each page, only here and there a few lines.
Page 530 - On returning to our anchored boat, we learned that when the flag was hoisted the horn-sounds were heard, that they were succeeded after a little time by the whistle-sounds, and that both increased in intensity as the evening advanced. On our arrival of course we heard the sounds ourselves.
Page 393 - ... velocities. The experiments of which the explanation will be given were as follows: — A light stem of glass, with pith-balls on its ends, was suspended by a silk thread in a glass flask, so that the balls were nearly at the same level. Some water was then put in the flask and boiled until all the air was driven out of the flask, which was then corked and allowed to cool. When cold there was a partial vacuum in it, the gauge showing from £ to £ of an inch pressure.
Page 537 - Admiralty Manual for ascertaining and applying the deviations of the compass caused by the iron in a ship.
Page 236 - ... it leaves much to be desired. Thus the alcohol and mercury are liable to get mixed in travelling, or even by merely holding the instrument in a horizontal position ; the indices also are liable either to slip if too free, or to stick if too tight. A sudden jerk or concussion will also cause the instrument to give erroneous readings by lowering the indices, if the blow be downwards, or by raising them, if the blow be upwards. Besides these drawbacks, the Six's thermometer causes...
Page 64 - The gun failed to be heard at a distance of 2-8 miles, and it yielded only a faint crack at 2^ miles. Meanwhile this investigation has given us a knowledge of the atmosphere in its relation to sound, of which no notion had been previously entertained. While the velocity of sound has been the subject of refined and repeated experiments, I am not aware that since the publication of a celebrated paper by Dr. Derham in the ' Philosophical Transactions...
Page 65 - I say, expresses the opinion generally entertained, " clear, still air" being regarded as the best vehicle for sound. We have not, as stated above, experimented in really dense fogs; but the experiments actually made entirely destroy the notion that clear weather is necessarily better for the transmission of sound than thick weather. Some of our days of densest acoustic opacity have been marvellously clear optically, while some of our days of thick haze have shown themselves highly favourable to...
Page 57 - By keeping every thing quiet on board, they were afterwards heard to a distance of 6 miles — a result, however, mainly due to the improved condition of the atmosphere. Considering the demands as to sound-range made by writers on this subject, the demonstrated incompetence of horns and whistles of great reputed power to meet these demands was not encouraging. On the 3rd of June the atmosphere had changed surprisingly. It was loaded overhead with dark and threatening clouds ; the sounds, nevertheless,...
Page 530 - ... calm, and the sea smooth. I thought we should be able to hear a long way off. We steamed beyond the pier end and listened. The steam clouds were there, showing the whistles to be active ; the smoke-puffs were there, attesting the activity of the guns. Nothing was heard. We went nearer ; but at two miles horns and whistles and guns were equally inaudible. This, however, being near the limit of the...

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