Memoir of James Prescott Joule

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Manchester Literary and Philosophical Society, 1892 - 196 pàgines
 

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Pàgina 98 - This I endeavoured to do, and discussion not being invited, the communication would have passed without comment if a young man had not risen in the section, and by his intelligent observations created a lively interest in the new theory. The young man was William Thomson...
Pàgina 97 - It was in the year 1843 that I read a paper ' On the Calorific Effects of Magneto-Electricity and the Mechanical Value of Heat ' to the chemical section of the British Association assembled at Cork. With the exception of some eminent men, among whom I recollect with pride Dr.
Pàgina 4 - The knowledge of the equivalency of heat to mechanical power is of great value in solving a great number of interesting and important questions.
Pàgina 111 - ... spent in conducting heat through a solid, what becomes of the mechanical effect which it might produce? Nothing can be lost in the operations of nature — no energy can be destroyed. What effect then is produced in place of the mechanical effect which is lost? A perfect theory of heat imperatively demands an answer to this question; yet no answer can be given in the present state of science.
Pàgina 61 - ... oxygen ; so that the whole heat of the system must still be referred to the chemical changes. But if the animal were engaged in turning a piece of machinery, or in ascending a mountain, I apprehend that in proportion to the muscular effort put forth for the purpose, a diminution of the heat evolved in the system by a given chemical action would be experienced.
Pàgina 177 - The contact theory,' he urged, ' assumes that a force which is able to overcome powerful resistance, as for instance that of the conductors, good or bad, through which the current passes, and that again of the electrolytic action where bodies are decomposed by it, can arise out of nothing : that without any change in the acting matter, or the consumption of any generating force, a current shall be produced which shall go on for ever against a constant resistance, or only be stopped, as in the voltaic...
Pàgina 178 - ... takes place. So we can change chemical force into the electric current, or the current into chemical force. The beautiful experiments of Seebeck and Peltier show the convertibility of heat and electricity ; and others by Oersted and myself show the convertibility of electricity and magnetism. But in no case, not even in those of the Gymnotus and Torpedo, is there a pure creation or a production of power without a corresponding exhaustion of something to supply it.
Pàgina 114 - that each atom of matter consists of a nucleus or central point enveloped by an elastic atmosphere, which is retained in its position by attractive forces, and that the elasticity due to heat arises from the centrifugal force of those atmospheres, revolving or oscillating about their nuclei or central points.
Pàgina 110 - In the present state of science, however, no operation is known by which heat can be absorbed into a body, without either elevating its temperature or becoming latent, and producing some alteration in its physical condition ; and the fundamental axiom adopted by Carnot may be considered as still the most probable basis for an investigation of the motive power of heat ; although this, and with it every other branch of the theory of heat, may ultimately require to be reconstructed on another foundation,...
Pàgina 46 - Now both the mechanical and heating powers of a current are, (per equivalent of electrolysis in any one of the battery cells,) proportional to its intensity. Therefore the mechanical and heating powers of a current are proportional to each other.

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