198 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



TABLE II. 

 Ratio of the Specific Volume at Various Temperatures to that at 4°. 



0.02 per cent. The specific volume of water is therefore 1.186 at 218°, 

 1.336 at 281°, and 1.434 at 306°. It is, according to our estimate of the 

 possible errors, almost certain that these values are not in error by as 

 much as 0.3 per cent, and it is probable that the error does not exceed 

 half this amount. Previous determinations* of the specific volume of any 

 considerable degree of accuracy have extended only up to 180°. 



Attention may also be called to the facts that the 0.1 normal solutions 

 between 218° and 306° expand appreciably (0.8 — 1.0 per cent) less than 

 pure water, but that the difference (0 2 per cent) between the solutions 

 of the two salts scarcely exceeds the experimental error. 



XL Experimental Data relating to the Conductivity 



Determinations. 



The Cell-Constant. — This was calculated from the conductivity mea- 

 surements at 26°, using for the specific conductivities of the 0.1 and 0.01 

 normal potassium chloride solutions the standard values of Kohlrausch, 

 Holborn, and Diesst'lhorst,t and for the other solutions the values at 18° 

 of Kohlrausch and Maltby,t and the temperature-coefficients of De- 

 guisne. § The quartz-crystal cup which was used for the first half of 



* Hirn, loc. cit. Waterston (Phil. Mag. (4) 26, 116-134, 1863) lias, to be sure, 

 made rough measurements from 210 to 320°; but this was done in a glass appa- 

 ratus which was greatly attacked. 



t Wied. Ann , 64, 440 and 4-j1 (1808). 



\ Wissensch. Abhandlungen phys.-techn. Reichsanstalt, 3, 210 (1900). 



§ Dissertation, Strassburg (1895); Kohlrausch and Holborn, Leitvermogen der 

 Elektrolyte, 199. 



