278 MR. W. R. BOUSFIELD AND DR. T. M. LOWRY ON THE ELECTRICAL 



TABLE VIII. Expansion of Aqueous Solutions of Sodium Hydroxide between 



C. and 100 C. 



The coefficients in the equation 



which are also given on Table VIII., were deduced from the final values for p , /> 18 , 

 /5o> Pioo an d wer e plotted against the percentage of soda in the solution. The 

 resulting curves were quite smooth, with the exception of a break at 12 per cent. 

 which was caused by the change from the cube to the square law ; this break might 

 have been avoided by giving to y a small negative value above 12 per cent., but as the 

 effect of this on the densities would have been unappreciable, it was thought better 

 not to reintroduce this coefficient when once it had vanished from the equation. 

 These coefficents were used to calculate the density of the solutions for every 

 2 per cent, at intervals of 10C. from 0C. to 100C., and the results are shown in 

 Table IX. The gradual change in the coefficients is well shown in Diagram II., which 

 also shows the difference curves for p pi 6 , PoPso an( ^ Po~Piw 



