In the case of the evaporation of water we are satisfied with the explanation given by the kinetic theory of gases and do not demand that to repeat a well-known jest of Huxley the disappearance of the " aquosity " be also taken into consideration . " ( pp . 14 15)
42.
In 1893, Nagaoka traveled to Europe, where he continued his education at the universities of Berlin, Munich, and Vienna, including courses on Saturn's rings and a course with Ludwig Boltzmann on his Kinetic Theory of Gases, two influences which would be reflected in Nagaoka's later work.
43.
It should also be noted that the theory of the Reynolds stress is quite analogous to the kinetic theory of gases, and indeed the stress tensor in a fluid at a point may be seen to be the ensemble average of the stress due to the thermal velocities of molecules at a given point in a fluid.
44.
He regarded heat as a form of motion, suggested the wave theory of light, contributed to the formulation of the kinetic theory of gases, and stated the idea of conservation of matter in the following words : " All changes in nature are such that inasmuch is taken from one object insomuch is added to another.
45.
One way to express the ideas that underlie that phrase in a more scientific manner can be found and described in the kinetic theory of gases : effusion or movement towards lower pressure occurs because unobstructed gas molecules will become more evenly distributed between high-and low-pressure zones, by a flow from the former to the latter.
46.
The ideal gas law can also be derived from first principles using the kinetic theory of gases, in which several simplifying assumptions are made, chief among which are that the molecules, or atoms, of the gas are point masses, possessing mass but no significant volume, and undergo only elastic collisions with each other and the sides of the container in which both linear momentum and kinetic energy are conserved.
47.
Well known examples include the heliocentric theory of planetary motion, the Bohr atom, the electromagnetic field, the kinetic theory of gases, gravitation, quarks, Mendelian genes, mass, velocity, etc . None of these constructs exists as a palpable entity occupying physical space .'He asked why psychology should be denied " the common right of every science to the use of hypothetical constructs or any theoretical speculation concerning causal explanations of its observable phenomena ?"
48.
:" As to the axioms of the theory of probabilities, it seems to me desirable that their logical investigation should be accompanied by a rigorous and satisfactory development of the method of mean values in mathematical physics, and in particular in the kinetic theory of gases . . . . Boltzmann's work on the principles of mechanics suggests the problem of developing mathematically the limiting processes, there merely indicated, which lead from the atomistic view to the laws of motion of continua ."
