|A Dewar flask (Ѻ) device for storing liquid nitrogen; conceptualized by Ernst Haeckel (c.1895) as a way to liquefy or solidify “soul” into a type of snow, i.e. “soul snow”, as he referred to it, if in fact soul did exist, e.g. as a form of gas or spiritual vapor.|
The concept of ‘soul-snow’ was posited in circa 1895 by German biologist Ernst Haeckel, as a type of humorous pun, who seems to have introduced the notion so as to disprove, in a ridiculing manner, the theory of the soul. 
● Gerard Nahum
● Thermodynamics of Hell
1. Connor, Steve and Leslie, Esther. (2009). “Master’s and Doctoral Program in Humanities and Cultural Studies Courses: Coldness: Toward a Political Thermodynamics of Culture”, LondonConsortium.com.
2. (a) Haeckel, Ernst. (1895–1899) Die Welträthsel ("world-riddle"); also spelled Die Welträtsel. Jena: Publisher.
(b) Haeckel, Ernst. (1905). The Riddle of the Universe: at the Close of the Nineteenth Century (ch. VI: The Nature of the Soul, pgs. 88-108; ch. XI: Immortality of the Soul, pgs. 188-210; ch. XII: The Law of Substance, pgs. 211-32; soul-snow, pg. 201), trans. Joseph McCabe. Harper & Brothers.
(c) The Riddle of the Universe – Wikipedia.