INTRODUCTION. 91 
very beautiful and instructive instance it is of that 
unerring skill and wisdom with which the whole 
constitution is ordered and kept in order, by Him, 
who, with minute accuracy, “ weigheth the mountains 
in scales, and the hills in a balance.”* 
The Ocean is never perfectly at rest: even be- 
tween the tropics, in what are called the calm 
latitudes, where the impatient seaman for weeks 
together looks wistfully but vainly for the welcome 
breeze; and where he realizes the scene so gra- 
phically described in “The Rime of the Ancient 
Mariner :”— 
“Day after day, day after day, 
We stuck, nor breath nor motion; 
Asidle as a painted ship, — 
Upon a painted ocean ;” 
even here the smooth and glittering surface is not 
at rest: for long, gentle undulations, which cause 
the taper mast-head to describe lines and angles 
upon the sky, are sufficiently perceptible to tan- 
talize the mariner with the thought that the breeze 
which mocks his desires, is blowing freshly and gal- 
lantly elsewhere. The most remarkable of the mo- 
tions observable in the sea, are the tides, periodical 
risings and fallings in the height of the surface, 
which take place twice every twenty-four hours, or 
nearly. It is now well ascertained that these mo- 
tions are caused by the attraction of the sun. and 
moon, but more particularly the latter, upon the 
particles of water, which moving freely among them- 
selves with little force of cohesion, readily yield to 
* Isa. xl, 12. 
