20 
Since they lie between adjacent isobaric surfaces their continuation 
must cease only by turning on themselves or by meeting the sides 
of the basin. V. Bjerknes has given the name “solenoid” to an 
isobaric-isosteric tube. It is convenient to select as a unit tube one 
included by isosteric surfaces constructed for intervals of 10~> of 
specific volume, and isobaric surfaces constructed for intervals of 
one centibar. Bjerknes has also called attention to the significance 
of solenoids by stating that the measure of the intensity of forces in 
a given vertical sectional area is in direct proportion to the number 
of solenoids running through it. This number depends upon the 
degree of stability and inclination; the greater the stability and the 
inclination, the greater the number of solenoids per unit cross- 
sectional area. 
EFFECT OF EARTH ROTATION ON OCEAN CURRENTS 
Dynamic tendencies of water particles have been discussed purely 
as indicated by mass distribution; now the behavior of such phenom- 
ena are traced in the form of actual motion on, and as qualified by, 
the veering surface of a rotating sphere. 
In order to understand the effect of earth rotation on currents, 
we might begin by studying very closely the absolute movement of 
a fixed body at the pole of a rotating sphere and another similar 
body on the equator. It will soon be perceived that the former 
enjoys a pure centric movement while the latter has a pure transla- 
tory motion, and any intervening point partakes a centric-transla- 
tory path. Bodies at rest relatively to the globe, as also the surface 
of the earth itself, are, strictly speaking, under a phase of centric 
and translatory motion, the relation between the two depending upon 
the geographical latitude. This phenomenon is very difficult to 
comprehend, since all of our senses are trained to accept the earth 
and resting bodies as a stationary base, and these remarks in so 
short a space, can hope to touch generalities only. Those who are 
interested in a detailed exposition of the subject are referred to 
Krummel (cf., Handbuch der Ozeanographie, vol. 2). Also Humph- 
reys (cf., ‘‘ Physics of the Air.’’ 1920). 
As long as all bodies remained in fixed relations, a state of “rest” 
may be said to prevail, by virtue of the fact that no variations from 
the relative positions exist. But distinction immediately arises 
whenever any free motion whatsoever, relatively to the earth, is 
introduced. At any other point on the earth’s surface than along 
the equator, due to the element of centricity previously described, 
divergence takes place between the straight path of a particle due 
solely to inertia, and the movement of other particles held fast to 
the surface of the earth and carried around with it as it rotates. 
This fact was proven years ago when the straight line of motion 
possessed by Focault’s pendulum swinging to and fro soon revealed 
