The Edinburgh New Philosophical Journal: Exhibiting a View of the Progressive Discoveries and Improvements in the Sciences and the Arts, Volumen1

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A. and C. Black, 1855
 

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Página 90 - To show the use of these terms, and explain the ideas of a store of energy, and of conversions and transformations of energy, various illustrations were adduced. A stone at a height, or an elevated reservoir of water, has potential energy. If the stone be let fall, its potential energy is converted into actual energy during its descent, exists entirely as the actual energy of its own motion at the instant before it strikes, and is transformed into heat at the moment of coming to rest on the ground....
Página 33 - Such was the state of the civilized world, when the Kelts, or Gauls, broke through the thin screen which had hitherto concealed them from sight, and began, for the first time, to take their part in the great drama of the nations. For nearly two hundred years they continued to fill Europe and Asia with the terror of their name ; but it was a passing tempest ; and, if useful at all, it was useful only to destroy.
Página 93 - Edinburgh, the author has shown that the sun's heat is probably* due to friction in the atmosphere between his surface and a vortex of vapours, fed externally by the evaporation of small planets, in a region of very high temperature round the sun, which they reach by gradual spiral paths, and falling in torrents of meteoric rain, down from the luminous atmosphere of intense resistance, to the sun's surface.
Página 45 - In the fourth century before the Christian era, " the Kelts or Gauls broke through the thin screen which had hitherto concealed them from sight, and began for the first time to take their part in the great drama of the nations. For nearly two hundred years they continued to fill Europe and Asia with the terror of their name : but it was a passing tempest, and if useful at all, it was useful only to destroy.
Página 376 - ... In the autumn this species is busily engaged in digging small holes in the bark of the pines and oaks, to receive acorns, one of which is placed in each hole, and is so tightly fitted or driven in that it is with difficulty extracted. Thus, the bark of a large pine, forty or fifty feet high, will present the appearance of being closely studded with brass nails, the heads only being visible.
Página 92 - ... all known vegetables get the greater part of their substance — certainly all their combustible matter — from the decomposition of carbonic acid and water absorbed by them from the air and soil. The separation of carbon and of hydrogen from oxygen in these decompositions is an energetic effect equivalent to the heat of recombination of those elements by combustion or otherwise. The beautiful discovery of Priestley, and the subsequent researches of Sennebier, De Saussure, Sir Humphrey Davy...
Página 92 - ... burning as much food as it has used during its life, and an amount of fuel that would generate as much heat as its body if burned immediately after birth. On the other hand, the dynamical energy of luminiferous vibrations was referred to as the mechanical power allotted to plants (not mushrooms or funguses, which can grow in the dark, are nourished by organic food like animals, and like animals absorb oxygen and exhale carbonic acid) to enable them to draw carbon from carbonic acid, and hydrogen...
Página 94 - ... the potential energy of the mutual gravitation of those bodies is gradually expended, half in augmenting their motions, and half in generating heat; and we may trace this kind of action either backwards or forwards; backwards for a million of million years with as little presumption as forwards for a single day. If we trace them forwards, we find that the end of this world as a habitation for man, or for any living creature or plant at present existing in it, is mechanically inevitable', and...
Página 97 - ... may, by their mutual gravitations, and by the resistance their motions must experience in the gaseous atmosphere, evaporated from them by the heat of their collisions after a vast period of time, come into a state of motion, heat, and light, analogous to the present condition of our solar system and the stars.
Página 94 - ... with this limitation to the certainty of all speculations regarding the future and pre-historical periods of the past, we may legitimately push them into endless futurity, and we can be stopped by no barrier of past time, without ascertaining at some finite epoch a state of matter derivable from no antecedent by natural laws. Although we can conceive of such a state of all matter, or of the matter within any limited space, and have cases of it in the arbitrary distributions of temperature, prescribed...

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