We find Prester John in one more phase before he vanishes from Asiatic history, real or mythical.
If all the water be frozen, we have the vapour pressure curve of ice OB; while, if the pressure be raised, so that all the vapour vanishes, we get the curve OC of equilibrium between the pressure and the freezing point of water.
If this vanishes for all values of X, u, v, ~, s~, ~ we must have X, Y, Z, L, M, N = o, which are the conditions of equilibrium.
As regards the polarization of the dispersed light as dependent on the angle at which it is emitted, we find that although, when terms of the second order are included, the scattered light no longer vanishes in the same direction as before, the peculiarity is not lost but merely transferred to another direction.
This stream flows north-westward from the last lake and vanishes underground within 3 m.