BREDGMAN. — MERCURY UNDER PRESSURE. 



373 



of volume of the water, which entered into the computation, are also 

 given, as this effect is rather large. Roughly, the correction intro- 

 duced by the water was about one third of the total effect due to the 

 change of volume of the mercury. These values for water were taken 

 from the values to be given in greater detail in the following paper. 



e 7 

 PRESSURE. KGM/CM'X Id? 



Figure 6. The deviations from linearity of the points obtained with one 

 piezometer. This shows the irregularities in the results introduced by internal 

 strains. 



Figure 6 gives the deviations of the observed points of two of the 

 sets of readings of Table I. from a straight line. This line, of the form 

 W = a + bp, does not happen to pass through the origin, but gives 

 A F = 0.001 at ;? = 0. All the deviation curves, therefore, start from 

 the point A.V = —0.00100. In Table II. are given the values calcu- 

 lated with the help of the deviation curves for the five piezometers at 

 pressure intervals of 500 kgm., together with the weighted mean of 

 these values. Finally in Table III. are shown the values calculated by 

 the parabolic formula, the weighted experimental values, the devia- 

 tions, and the finally accepted values, obtained with the smooth 

 deviation curve shown in Figure 7. 



The change of volume at any pressure and 0° may be found, either 

 by constructing a curve through the points of Table III., or more ac- 

 curately by computing at any pressure the change of volume by the 

 formula 



Ay = ap + bp\ 



