Table of Candidate Massic Heatabilities
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Experiments by James Prescott Joule and others in the 1840'sd=|1090'sz established the mechanical equivalence of heat and work. But this understanding came only after units for temperature and heat had already been devised on an ad hoc basis. The Fahrenheit degree or Rankine degree, and the Celsius degree or kelvin had been selected with the purpose of making their scales convenient. Units of heat such as the calorie, the kilocalorie, and the British thermal unit (BTU) were derived in terms of these temperature units, without attempting to make them coherent with mechanical units.
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For convenience, Primel chooses the value for its ⚀masselic·heatabilitel so that the range from the freezing point to the boiling point of water is exactly a dozenally-round 190z=|252d ⚀stadegrees. This puts the ⚀masselic·heatabilitel at 4198.76286389748d joules per kelvin per kilogram. This is a bit above the mean value for water, but slightly under the value of 4204d joules per kelvin per kilogram which occurs at 4°C, near water's maximum density. This puts the ⚀temperaturel at ≈ 0.49186ᘔ35×10−4z ≈ |1.91370272388791×10−5d kelvin, or 0.86ᘔ351×10−4z ≈ 3.44466490299824×10−5d degrees Fahrenheit, and the ⚀quadqua·temperaturel or ⚀stadegree at exactly 5/7 of a Fahrenheit or Rankine degree (0.714285d= |0.86ᘔ351z °F), or exactly 25/63d = |21/53z of a kelvin or Celsius degree (0.396825d K = |0.49186ᘔ35z K). Primel makes this choice solely in order to make temperature conversions between Primel units and conventional units relatively simple rational numbers that may be computed exactly. It should not be taken to imply that Primel units are in any way "based" on conventional units.
(Tom Pendlebury took a similar approach when he derived the Calg, the coherent unit of temperature for his TGM metrology. He chose his masselic·heatabilitel, the Calsp, in such a way that 1 biqua·Calg (colloquialized as 1 bigree) equals exactly one decikelvin (0.1d kelvin, or 0.18d °F), and 1 triqua·Calg (colloquialized as 1 tregree) equals exactly 1.2d kelvin (or 2.16d °F). This was solely in order to make conversions to conventional units simple and exact, and does not imply that TGM's units are "based" on the decikelvin. However, that choice does set the Calsp to a value (about 4177d joules per kelvin per kilogram) just under the minimum for the natural range for water, making for a slightly uneasy compromise. A close approximation of the bigree in Primel would be the ⚀quarter·stadegree aka the ⚀colossal·temperature or ⚀colossegree (exactly 5/28d = |0.17857142d= |0.286ᘔ351z °F, or exactly 25/252d = |0.09920634d= |0.1235186ᘔz K). Primel would approximate the tregree with the ⚀trina·stadegree aka the ⚀turrial·temperature or ⚀turregree (exactly 15/7d = |2.142857d= |2.186ᘔ35z °F
Primel provides three temperature scales based on the ⚀stadegree, with different choices for a zero point:
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