In thermodynamics, negative transformation, as contrasted with a positive transformation, is the transformation that results from the conversion of heat into work and therefore of heat from lower to higher temperature. 
Clausius footnotes this 1854 version of the negative transformation definition with the comment “the reason why this choice of positive and negative senses is preferable to the opposite one, will become apparent after the theorems relative to the transformations have been enunciated (1864). The exact details of this 1864 asterisk remain to be tracked down, but seem to refer the 1864 "Appendix to the Fifth Memoir: On Some Approximate Formula employed to Facilitate Calculations. 
● Positive work
● Negative work
● Double transformation
● Uncompensated transformation
● Transformation content
● Equivalence-value of all uncompensated transformations
1. Clausius, Rudolf. (1865). The Mechanical Theory of Heat (negative transformations, pg. 128). John van Voorst.
2. Clausius, Rudolf. (1865). The Mechanical Theory of Heat (pgs. 208-14). John van Voorst.