The Second Law of Thermodynamics: Memoirs by Carnot, Clausius, and Thomson
Reflections on the motive power of heat by Sadi Carnot -- On the motive power of heat and on the laws which can be deduced from it for the theory of heat, by R. Clausius -- The dynamical theory of heat. -- By W. Thomson (Lord Kelvin).
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according already amount appears application assumed assumption atmospheric becomes body calculated called caloric Carnot's changes Clausius column complete compression conclusions condition connection consequently considered constant contained corresponding demonstration denote density determined developed dynamical theory engine equal equation equivalent established exactly expansion experimental experiments expression external fluid force former formula function fundamental further gases given gives increase Joule latent limits liquid magnitude maximum means mechanical effect motion motive power necessary numbers observations obtain operations original perature possible power of heat present pressure principle probable produced proportional proposition quantity of heat raised range of temperatures reasoning referred relation remains remarked represented respect result saturated shows specific heat steam substance suppose taken temper temperature theory of heat thermal tion transfer unit vapor volume water vapor weight whole
Page 118 - It is impossible for a self-acting machine, unaided by any external agency, to convey heat from one body to another at a higher temperature ; or heat cannot of itself (that is, without compensation) pass from a colder to a warmer body.
Page 124 - ... substances at the same temperature, was first given (although not in precisely the same terms) by CARNOT, and demonstrated by him, according to the principles he adopted. We have now seen that its truth may be satisfactorily established without adopting the false part of his principles. Hence all CARNOT'S conclusions, and all conclusions derived by others from his theory, which depend merely on equation (3), require no modification when the dynamical theory is adopted. Thus, all the conclusions...
Page 120 - ... that, when an electrical current is continuously produced from a purely thermal source, the quantities of heat evolved electrically in the different homogeneous parts of the circuit are only compensations for a loss from the junctions of the different metals, or that, when the effect of .the current is entirely thermal, there must be just as much heat emitted from the parts not affected by the source as is taken from the source.
Page 10 - ... quantity by the compression of the elastic fluids. This preliminary idea being established, let us imagine an elastic fluid, atmospheric air for example, shut up in a cylindrical vessel, abed (Fig. 1), provided with a movable diaphragm or piston, cd. Let there be also two bodies, A and B, kept each at a constant temperature, that of A being higher than that of B.
Page 132 - I cannot see that any hypothesis, such as that adopted by Clausius fundamentally in his investigations on this subject, and leading, as he shows to determinations of the densities of saturated steam at different temperatures, which indicate enormous deviations from the gaseous laws of variation with temperature and pressure, is more probable, or is probably nearer the truth, than that the density of saturated steam does follow these laws as it is usually assumed to do. In the present state of science...
Page 111 - To distinguish this motion from others, and to signify the cause of our sensation of heat," and of the expansion or expansive pressure produced in matter by heat, "the name repulsive motion has been adopted *." 2. The dynamical theory of heat, thus established by Sir Humphry Davy, is extended to radiant heat by the discovery of phenomena, especially those of the polarization of radiant heat, •which render it excessively probable that heat propagated through "vacant space," or through diathermanic...
Page 115 - If an engine be such that, when it is worked backwards, the physical and mechanical agencies in every part of its motions are all reversed (see § 89), it produces as much mechanical effect as can be produced by any thermodynamic engine, with the same temperatures of source and refrigerator, from a given quantity of heat.
Page 112 - Natur^, which contains some correct views regarding the mutual convertibility of heat and mechanical effect, along with a false analogy between the approach of a weight to the earth and a diminution of the volume of a continuous substance, on which an attempt is founded to find numerically the mechanical equivalent of a given quantity of heat. In a paper published about fourteen months later, " On the Calorific Effects of Magneto-Electricity and the Mechanical Value of HeatJ,
Page 116 - If this axiom be denied for all temperatures, it would have to be admitted that a self-acting machine might be set to work and produce mechanical effect by cooling the sea or earth, with no limit but the total loss of heat from the earth and sea, or, in reality, from the whole material world.
Page 117 - Carnot himselff ; and that it is false, where mechanical work is, on the whole, either gained or spent in the operations, may (as I have tried to show above) be considered to be perfectly certain. It must then be admitted that Carnot's original demonstration utterly fails, but we cannot infer that the proposition concluded is false. The truth of the conclusion appeared to me, indeed, so probable, that I took it in connexion with Joule's principle, on account of which...