[39] The Chancellor continued to take to the end of his life a warm interest in the work at the laboratory. In 1887, the Jubilee year, as Proctor--at the same time I held the office of Demonstrator--it was my duty to accompany the Chancellor and other officers to Windsor to present an address from the University to Her Majesty. I was introduced to the Chancellor at Paddington, and he at once began to question me closely about the progress of the laboratory, the number of students, and the work being done there, showing himself fully acquainted with recent progress. [40] In 1894 the list contained, in Part II., sixteen names, and in Part I., one hundred and three names. [41] Under the new regulations Physics was removed from the first part of the Tripos and formed, with the more advanced parts of Astronomy and Pure Mathematics, a part by itself, to which only the Wranglers were admitted. Thus the number of men encouraged to read Physics was very limited. This pernicious system was altered in the regulations at present in force, which came into action in 1892. Part I. of the Mathematical Tripos now contains Heat, Elementary Hydrodynamics and Sound, and the simpler parts of Electricity and Magnetism, and candidates for this examination do come to the laboratory, though not in very large numbers. The more advanced parts both of Mathematics and Physics are included in Part II. [42] “Life of J. C. Maxwell,” p. 383. [43] “Statique Expérimentale et Théorique des Liquides soumis aux seules Forces Moléculaires.” Par J. Plateau, Professeur à l’Université de Gaud. [44] The “Red Lions” are a club formed by Members of the British Association to meet for relaxation after the graver labours of the day. [45] “Leonum arida nutrix.”--_Horace._ [46] _v.r._, endless. [47] “Life of J. C. Maxwell,” p. 394. [48] “Life of J. C. Maxwell,” p. 404. [49] In his “Hydrodynamics,” published in 1738, Daniel Bernouilli had discussed the constitution of a gas, and had proved from general considerations that the pressure, if it arose from the impact of a number of moving particles, must be proportional to the square of their velocity. (_See_ “Pogg. Ann.,” Bd. 107, 1859, p. 490.) [50] The proof is as follows:-- If σ be the specific heat at constant volume, σ′ at constant pressure, and consider a unit of mass of gas at pressure p and volume v, let the volume increase by an amount dv, while the temperature dy. Thus σ′dT = σdT + pdv But pv = ⅔T/m Hence p being constant, pdv = ⅔ dT/m Therefore σ′ = σ + ⅔ 1/m Now suppose an amount of heat, dH, is given to a single molecule and that its temperature is T. Its specific heat is σ, and dH = σmdT But dH = βdT Therefore β = σm Hence 1/m = σ/β Thus σ′ = σ(1 + 2/(3β)) And σ′/σ = γ Therefore γ = 1 + 2/(3β) Or β = 2/(3(γ-1))