DENSITY OF SOLUTIONS — MORRISON. 



135 



The only results by which we can check the above are Nicol's 

 single observation* and Favre and Valson's series of observa- 

 tions.j- Nicol found that a solution consisting of half a mole- 

 cule of crystallised salt to 100 of water has, at 20° C, a specific 

 gravity, relatively to water at 20° C, of 1.04296, or, as a simple 

 calculation will show, that a solution containing 3.9711 per cent, 

 of anhydrous salt has a density, in grms. per cu. cm., of 1.04116. 

 Graphical treatment of my observations gives 1.0408 as the 

 density of this solution. The weakest solution examined by 

 Favre and Valson consisted of 14.05 parts of crystallised salt 

 and 100 parts of water, and therefore contained 6.772 per cent, 

 of anhydrous salt. The next weakest contained about twice this 

 percentage. The densities of solutions so strong as these cannot 

 be found by the aid of my observations above. But if a curve 

 of densities versus percentage compositions be plotted by means 

 of my observations and theirs combined, it shows no discontinu- 

 ity between the two portions. 



The following formula represents to the fourth decimal place 

 the densities of solutions of this salt up to a concentration of 

 about 2.5 per cent. : — 



D20 ^ 0.99827 + 0.0164 25. 



The densities calculated by means of this formula are given in 

 the third column of the above table, and the amounts by which 



* Phil. Mag., Ser. 5, Vol. XVI, (1883), p. 122. 

 t Comp. Rend., T. LXXIX, p. 908. 



