Salt is an important export, being manufactured in salt water swamps and marshes throughout the province of Pangasinan (whose name, from **asin**, " salt," means "the place where salt is produced").

To illustrate the main features of the calculation, we may suppose that the surface is subject to a simple-harmonic cycle of temperature variation, so that the temperature at any time t is given by an equation of the form 0 - 0 0 = **Asin** 27rnt= A sin 27rt/T, (5) where 0 0 is the mean temperature of the surface, A the amplitude of the cycle, n the frequency, and T the period.

(1) Words which have their, radical termination in n but which in the singular drop that n, resume It in the plural before I: homin-ein makes ome in the singular and omens in the plural; **asin-u-rn** makes ase and asens.