Calorus

Calorus, a bronze-armoured knight with a sealed glass chest-plate of glowing fluid, is pierced by a blunt borer; from the wound pours heat-shimmer, not fluid, and the vessel stays full.

The Physics

Antoine Lavoisier’s Traité élémentaire de chimie (1789) listed caloric, a conserved, weightless heat fluid, among the elements. In 1798 Count Rumford reported that boring a cannon with a blunt borer kept producing heat seemingly without limit, enough to boil water in about two and a half hours, and argued that heat is a form of motion. The fluid picture faded around 1850, when J. P. Joule’s “On the mechanical equivalent of heat” and Rudolf Clausius’s founding paper of thermodynamics made heat a transfer of energy, not a substance.

ΔU = Q − W

Joule 1850: 772 ft·lbf per Btu ≈ 4.15 J per calorie (modern: 1 cal_th = 4.184 J exactly)

• ΔU: change in a system’s internal energy (J)
• Q: heat added to the system (J)
• W: work done by the system (J)
• ft·lbf: foot-pound-force, ≈ 1.356 J
• Btu: heat to warm one pound of water by 1 °F, ≈ 1055 J
• cal_th: thermochemical calorie (J)

The first law says heat and work are two ways of moving the same energy, so there is no stock of caloric to run out of, and none to conserve. Rumford’s borer converted mechanical work W into internal energy indefinitely. Sources: Rumford, Phil. Trans. R. Soc. 88, 80 (1798), doi:10.1098/rstl.1798.0006; Joule, Phil. Trans. R. Soc. 140, 61 (1850), doi:10.1098/rstl.1850.0004; Clausius, Ann. Phys. 155, 368 (1850), doi:10.1002/andp.18501550306.

Honest caveat: Heat-fluid ideas are older than 1789; Lavoisier named and listed caloric. Rumford’s result was not accepted as decisive at the time, and 1850 is a conventional end date, marked by Joule’s and Clausius’s 1850 papers; caloric theory faded gradually.

In character

They pierced me and waited for me to drain. I never did. Whatever pours out of me is motion, and the more they bore, the more I give.

On the hoodie

Front: a cracked glass flask holding a flame, with a borer across it. Back: Calorus in full pixel art with the character name and printed dates for the theory (RUMFORD 1798 - JOULE 1850). Gildan 18500 Heavy Blend hoodie, Black, S to 5XL.

Part of the Ghost Particles That Were Wrong set with Sir Aetheron, Enrayne, Diphantom, Prematura, Thetarch. Browse all physics hoodies, more thermodynamics designs, or the Deep Cuts.