In thermodynamics, Gustav Zeuner (1828-1907) was a German physicist notable for a number of publications in the early developmental stages of thermodynamics, the first being his 1859 Fundamentals of the Mechanical Theory of Heat (Grundzüge der Mechanischen Wärmetheorie).  His central textbook, deriving from his 1859 paper and intended for his lectures at the Technical High School at Dresden, was the 1887 Technical Thermodynamics, which went through five editions, turning eventually into a two-volume set. 
Dresden school of thermodynamics
In schools of thermodynamics, Zeuner, in some circles, is considered as the founder of the "Dresden school of thermodynamics". Specifically, in 1873, Zeuner took on the post of director at the Royal Saxon Polytechnicum in Dresden (now Technische Universität Dresden). Zeuner's efforts there led to the introduction of the humanities; the extension of the range of subjects taught resulted in the polytechnic's rise to a full-scale polytechnic university in 1890. In 1889, aged 61, Zeuner gave up his position as director of the polytechnic to work as a lecturer until his retirement in 1897. Those physicists, engineers, and thermodynamicists educated at Dresden during Zeuner’s oversight are said to have come from the Dresden school of thermodynamics.
In relation to German physicist Rudolf Clausius’ description of internal energy U of a body, in his 1879 Mechanical Theory of Heat, he has disagreement with Zeuner’s description and interpretation of a “quantity called U”, used by Zeuner, which in 1860 Zeuner calls “interior heat” of the body and in 1866 calls “internal work” of the body. 
1. Treavor, J.E. (1901). “Technische Thermodynamik (Technical Thermodynamics)” (book review) (pgs. 603-04), The Journal of Physical Chemistry, American Chemical Society, Faraday Society, Chemical Society (Great Britain).
2. (a) Zeuner, Gustav. (1907). Technical Thermodynamics (Volume I: Fundamental Laws of Thermodynamics, Theory of Gases), New York: D. Van Nostrand Co.
(b) Zeuner, Gustav. (1907). Technical Thermodynamics (Volume II: The Theory of Vapors), New York: D. Van Nostrand Co.
3. Clausius, Rudolf. (1879). The Mechanical Theory of Heat, (pg. 18). London: Macmillan & Co.