Section 12. Summary of Specific-Volume Values. 37 



The results with the 0.002 normal solution may be regarded as com- 

 pletely identical with those that would be obtained with pure water ; for 

 this solution contains only about 0.01 per cent of salt ; and, moreover, the 

 experiments themselves show that there is no difference between the 

 specific-volume ratio of the 0.002 and 0.01 normal solutions, and that the 

 difference between the latter and that of the 0.1 normal solution is some- 

 what less than 1 per cent, which indicates that the order of magnitude 

 of the difference between pure water and the 0.002 normal solution is 

 0.02 per cent. The specific volume of water is therefore 1.187 at 218, 

 1.337 at 281, and 1.437 at 30G. 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 water at high 

 temperatures have been made by Hirn up to 180, by Waterston* up to 

 320, and by Ramsay and Youngf up to 270. The values obtained by 

 interpolation from the older results of Waterston are 1.194 at 218, 1.355 

 at 281, and 1.454 at 306, which are seen to be considerably higher than 

 ours. Ramsay and Young, however, found 1.188 at 218 in substantial 

 agreement with our value. 



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

 between 218 and 306 expand appreciably less than pure water, but that 

 the difference between the solutions of the two salts scarcely exceeds the 

 experimental error. 



13. THE CONDUCTANCE-CAPACITY OF THE APPARATUS. 



The conductance-capacity was calculated from the conductance meas- 

 urements at 26, using for the specific conductances of the 0.1 and 0.01 

 normal potassium chloride solutions the standard values of Kohlrausch, 

 Holborn, and Diesselhorst,$ and for the other solutions the values at 18 

 of Kohlrausch and Maltby,|| and the temperature-coefficients of Deguisne. 

 The quartz-crystal cup which was used for the first half of the meas- 

 urements (cell 1) was accidentally broken, and a new one had to be 

 substituted for the rest of the work. After making three experiments 

 with the new cup, the platinum lining of the lower part of the 

 bomb had to be removed and repaired, and this operation changed the 

 conductance-capacity. The term cell n a will be used to characterize the 

 bomb as it was in these first three experiments with the new cup, and the 



*PhiI. Mag. (4) 26, 124 (1863). 

 tPhil. Trans. (A), 183, 109 (1892). 

 iWied. Ann., 64, 440 and 451 (1898). 



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

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

 Elektrolyte, 199. 



