4go 
Analyses of Books . 
[August, 
Ocean and Air Currents. By T. D. Smellie. Glasgo . J. 
Smith and Sons. Edinburgh : W. Blackwood and Sons. 
London : E. and F. N. Spon. 
The author commences his researches with the following simple 
experiment “ If you take a flat-bottomed circular vessel, termed 
to devolve horizontally, partially fill it with water, and ma ' e 
revolve gently, you will find the vessel at first slip from under the 
water, so as to give the water relatively a backward motion. ; 
similar result will follow if you try different speeds within 
the limits of the water being free to take its own motio 
the greater the speed the greater the backward motion. Alter 
a few revolutions the water will begin to acquire some 
forward motion of the vessel ; this will decrease the backward 
motion; and if continued long enough to allow the water 
acquire as much of the vessel’s motion as it will acqu.re, , it w 
take almost, but not quite, the same motion, for the water toward 
the surface will still lag behind the vessel.’ 
This illustrates on a small scale what actually takes place 
our globe. The earth turns eastward, and the water ol the seas, 
lagging behind, forms what appears as a current westwards 
This current is of course most marked where the rotation of the 
earth is most rapid, that is, in the equatorial regions. It these 
regions were open sea all round the globe, we should have simp y 
one uniform westward current ; but as the way « barred by the 
continents of America and Africa, and is much broken by the 
Eastern Islands which lie in the track of the current, - 
continuous stream is possible. In ithe Atlantic .when this giea 
current approaches the coast of America, it is deflected in two 
branches ; the smaller goes southwards, whilst the larger, ow » 
to the trend of the coast, turns northwards and forms, among 
other currents, the Gulf Stream. A part of this goes up into the 
Polar Sea, and another part southwards towards the coast of 
Africa to feed the central westward current. In the Pacific and 
Indian Oceans we have corresponding phenomena. . , 
The same “lagging behind” must produce the chief aerial 
currents — the trade-winds. . , . • . , 
The author’s theory is not merely the simplest and most intel- 
ligible explanation of oceanic and atmospheric currents, but 
seems best to account for the phenomena as observed. We 
strongly recommend this pamphlet to all who are intei ested 
meteorology and physiography. 
