The analogous reversible heat effects which occur at the junction of a metal and an electrolyte were also investigated by Jahn, but he did not succeed in obtaining so complete an agreement with theory in this case.
A comparison of the transformation of polymorphs leads to a twofold classification: (1) polymorphs directly convertible in a reversible manner - termed " enantiotropic " by O.
(6) If we apply the second law, regarding the couple as a reversible engine, and considering only the reversible effects, we obtain (s' - s")/T = - d(P/T)/dT.
The frame cases - wired on both sides - are hung at the angles of a revolving ring of iron, and the reversing process is so simple and effective that the " Cowan " reversible frame has been adopted in all the best machines.
The weave produces a reversible cloth, and it is extensively used for the embellishment of quilts and other fancy goods.
(5) If we might also regard the couple as a reversible thermodynamic engine for converting heat into work, and might neglect irreversible effects, such as conduction, which are independent of the current, we should expect to find the ratio of the heat absorbed at the hot junction to the heat evolved at the cold junction, namely, PIP', to be the same as the ratio T/T of the absolute temperatures of the junctions.
The Hungarian peasants are very fond of their natural brown sheep coats, the leather side of which is not lined, but embellished by a very close fancy embroidery, worked upon the leather itself; these garments are reversible, the fur being worn inside when the weather is cold.
The formation of an ester by the interaction of an acid with an alcohol is a "reversible" or "balanced" action, for as M.
The temperature must not be allowed to rise beyond a certain point, for the reaction NaC1+ NH 4 HC03= NaHCO 3 4-NH 4 C1 is reversible, and at a temperature of about 60° or 70° C. it is in fact practically going the wrong way, viz.
It may be stated that while in certain instances the union of toxin and antitoxin may be reversible, all the facts established cannot be explained on this simple hypothesis of reversible action.
Considered thermodynamically, voltaic cells must be divided into reversible and non-reversible systems. If the slow processes of diffusion be ignored, the Daniell cell already described may be taken as a type of a reversible cell.
The cell, together with this balancing electromotive force, is thus a reversible system in true equilibrium, and the thermodynamical reasoning applicable to such systems can be used to examine its properties.
Now a well-known relation connects the available energy of a reversible system with the corresponding change in its total internal energy.
Any reversible cell can theoretically be employed as an accumulator, though, in practice, conditions of general convenience are more sought after than thermodynamic efficiency.
If secondary effects are eliminated, the deposition of metals also is a reversible process; the decomposition voltage is equal to the electromotive force which the metal itself gives when going into solution.
But his best known contribution to general chemistry is his work on the phenomena of reversible reactions, which he comprehended under a general theory of " dissociation.
There were arrangements for the brilliant illumination of the choir and its relief, which was sometimes sculptured on both sides and reversible, while the podia were intentionally more obscure.
If, starting from E, the same amount of heat h is restored at constant pressure, we should arrive at the point F on the adiabatic through B, since the substance has been transformed from B to F by a reversible path without loss or gain of heat on the whole.
Special reversible paddle steamers (called doubleenders) were designed for service in the inlets and estuaries, and sixty-six ironclads were built and employed during the four years.
A very important evolutionary principle is that in such secondary returns to primary phases lost organs are never recovered, but new organs are acquired; hence the force of Dollo's dictum that evolution is irreversible from the point of view of structure, while frequently reversible, or recurrent, in point of view of the conditions of environment and adaptation.
A carefully made ship's compass is usually employed, though in some cases the compass card, with its attached magnets, is made reversible, so that the inclination to the zero of the card of the magnetic axis of the system of magnets attached to the card can be eliminated by reversal.
In the absence of such a reversible card the index correction must be determined by comparison with a unifilar magnetometer, simultaneous observations being made on shore, and these observations repeated as often as occasion permits.
The available energy A is the work which may be gained from the system by a small reversible isothermal operation with an osmotic cylinder, that is Pdv.
Nevertheless, the relations obtained in reversible cases such as sulphur have not yet found application in the highly interesting cases of ordinary irreversible isomerism.
The reversible character of the principal reaction has the consequence that a considerable portion of the sodium chloride (up to 33%) is lost, being contained in the waste calcium chloride solution which issues from the ammonia stills.
We are probably safe in saying, however, that the molecules of a toxin are not identical but vary in the degree of their combining affinities, and also in their toxic action, and that, while in some cases the combination of anti-substances has been shown to be reversible, we are far from being able to say that this is a general law.
Another difficulty arose from the fact that the reaction S02+O=S03 is reversible, the opposite reaction, SO 3 = S0 2 -f 0 setting in but little above the temperature required for the synthesis of SO 3.
- Diagram of Apparatus for there must be a reversible Demonstrating the Thomson Effect.
In Thomson's theory it is expressly assumed that the reversible thermal effects may be considered separately without reference to conduction.
In virtue of relations (2), the change of entropy of a substance between any two states depends only on the initial and final states, and may be reckoned along any reversible path, not necessarily isothermal, by dividing each small increment of heat, dH, by the temperature, 0, at which it is acquired, and taking the sum or integral of the quotients, dH/o, so obtained.
Nevertheless, the theoretical possibility, and its realization in many cases, has brought considerations to the front which have recently become of predominant interest; consequently the possible transformations of isomers and polymers will be considered later under the denomination of reversible or dynamical isomerisms.