480 C. Bar us — Fluid Volume and its 



At this stage of progress, the point of view gained in the 

 extensive researches of Ramsay and Young 1 throws new light 

 on the subject. They prove experimentally that if pressure^? 

 and temperature vary linearly (p= b0 — a), the substance 

 operated on does not change in volume. Ether, methyl and 

 ethyl alcohol, acetic and carbonic dioxide are tested. Excep- 

 tional values for the case of acetic acid and nitrogen tetroxide 

 are referred to dissociation. Utilizing James Thomson's 2 dia- 

 gram, they point out that the locus of the isothermal minima 

 and maxima intersect the locus of maximum vapor tensions 

 at the critical point. Data are given for ether. Fitzgerald 3 

 reasoning from Ramsay and Young's results arrived at the 

 theoretic results virtually given by Levy (see above). Tait 4 

 who is still actively at work on high pressures has recently 

 made further publication on the effect of dissolved substances 

 on internal pressure. An endeavor to formulate Andrew's 

 classical results is due to Dickson. 5 Fitzgerald 6 recently applied 

 Clausius's 7 equation to a discussion of Ramsay and Young's data, 

 and Sarrau 8 has similarly discussed Amagat's data. 



3. A few references to thermal expansion of liquids, which 

 enters incidentally into the present paper, must be added. 

 Many formulse have recently been devised and tested by 

 Avenarius, 9 DeHeen, 10 Mendeleeff, 11 Thorpe and Riicker, 12 Jouk 13 

 and others, 14 not to mention older observers. None of these 

 forms are satisfactory when long ranges of temperature are in- 

 troduced, as was shown by Bartoli and Stracciati, 16 testing 

 Mendeleeff's, and Thorpe and Rucker's formulae, and by the 

 discussion between Mendeleeff and Avenarius. 



Special mention must be made of the celebrated papers of J. 

 Willard Gibbs, 16 by whom the scope of graphic methods for 

 exhibiting the thermo- dynamics of fluids w T as surprisingly 



1 Ramsay and Young: Phil. Mag., (5) xxiii, p. 435, 1887 ; ibid., xxiv, p. 196, 

 188*7; Proc. Roy. Soc. Lond., xlii, p. 3, 1887. 



2 James Thomson: Phil. Mag., (5), xliii, p. 227, 1872; Nature, ix, p. 392, 1873. 



3 Fitzgerald: Proc. Roy. Soc, xlii, p. 50, 1887. 



4 Tait: Challenger Reports, Phys. and Chem., ii, (4), 1888; Proc. Roy. Soc. 

 Ed., xv, p. 426, 1888. 



5 Dickson: Phil. Mag., x, p. 40, 1880. 



6 Fitzgerald: Proc. Roy. Soc. Lond., xlii, p. 216, 1887. 



7 Clausius: Wied. Ann., p. 337, 18 . 



8 Sarrau: C. R-, xciv, pp. 639, 718, 845, 1882; ibid., ci, p. 941, 1885. 



9 Avenarius: Beibl., ii, p. 211, 1878; ibid., viii, p. 806, 1884. 



10 DeHeen: Bull. Ac. Roy. Belg., (3), iv, p. 526, 1882 ; Journ. Chem. Soc, xlv, 

 p. 408, 1884. 



11 Mendeleeff: Chem. Ber., xvii, p. 139, 1884; Beibl, viii, p. 806, 1884. 



12 Thorpe aud Riicker: Journ. Chem. Soc, xlv, p. 135, 1884. 



13 Jouk: Beibl., viii, p. 808, 1884. 



14 Rosenberg: Journ. d' Almeida, vii, p. 350, 1878. 



15 Bartoli and Stracciati : Beibl., ix, p. 510, 1885. 



16 J. Willard Gibbs: Trans. Conn. Acad., ii, (2), pp. 309, 382, 1873. 



