Act III. Equivalence, Conservation, Interconvertibility: When and of What?

Abstract

That heat could sometimes cause mechanical effect, and much of it, had been known since the disaster that befel Strepsiades while he was cooking the haggis for the feast of Zeus, but apparently it was the sooty proliferation of the steam engine in the early nineteenth century that first roused physicists to pay much attention to the phenomenon. As Carnot had seen, and as Clapeyron had made widely known, by absorbing and emitting heat a given body undergoing a cyclic process may do a definite amount of work, and by doing work cyclically a body may absorb and emit definite amounts of heat. Certain ideal bodies, described by the theory of calorimetry, give out in undergoing the reverse of a given process the heat they would gain and the work they would do in the given process.

… noi ci mettemmo per un bosco che da neun sentiero era segnato.

Non fronda verde, ma di color fosco; non rami schietti, ma nodosi e ’nvolti….

Dante, Inferno XIII, 2–5.