In existographies, William Irvine (1743-1787) (CR:2) was an Scottish chemist and physician noted for having done research in the 1770s on specific heat, furthering the earlier 1760 ideas of his mentor Joseph Black on this same topic, to outline a concept of “absolute heat”, differing from Black’s ideas to some extent. “Irvine’s particular theory was basically very simple in that the took the concept of ‘quantity of heat’ to its logical conclusion. Each and every body, according to Irving, contains a certain ‘absolute quantity of heat’, which is fixed by its heat capacity and its absolute temperature. If, for any reason, the heat capacity of a body should change then it must either emit or absorb heat; thus, the heats of combustion, of chemical reactions in general and the latent heats of fusion and vaporization are merely the consequences of abrupt changes in the heat capacities of the substances concerned. In fact, all productions or absorptions of heat indicate changes in heat capacity. Now this theorem enabled Irvine and his followers to calculate the absolute zero of temperature.”— Donald Cardwell (1971), From Watt to Clausius (pg. 55)
“Capacity for heat of a body is the number of units of heat required to raise one pound weight of the body one degree in temperature.”— William Irvine (c.1780), attributed [1]