FLUIDITY AND TEMPERATURE

139

working at 1, 5, and 23° at pressures ranging from 1 to 600
atmospheres and using pure water and four solutions of sodium
chloride of different concentrations. The nature of his results
is shown in Figs. 50 to 54. In Fig. 50 the percentage change
in the time of flow, [(ti — tp)/ti]10Q, is plotted as ordinates

FIG. 53,

FIG. 50.

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V
X

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gf

X

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12 16 20 24

FIG. 51. FIG. 52. FIG. 54.
The effect of pressure on the viscosity of aqueous solutions. (After Cohen.)
against the pressures as abscissas. It is observed that the vis-
cosity continues to decrease for all pressures up to 900 atmos-
pheres, but the decrease becomes yery slight at 23°. In Fig. 51
the ordinates are the same as before but the temperatures are
plotted as abscissas. It is evident that the'curves are approach-
ing each other and the zero axis, and thus they indicate the
possibility that at some higher temperature the curves will cross