THE ATMOSPHERE. 69 



92. An examination into the economy of the miiverse will be 

 sufficient to satisfy the well-balanced minds of observant men 

 that the laws which govern the atmosphere and the laws which 

 govern the ocean (§ 67) are laws which were put in force by the 

 Creator when the foundations of the earth were laid, and that, 

 therefore, they are laws of order ; else, why should the Gulf 

 Stream, for instance, be always where it is, and running from the 

 Gulf of Mexico, and not somewhere else, and sometimes running 

 into it ? Why should there be a perpetual drought in one part of 

 the world, and continual showers in another ? Or why should the 

 winds and sea obey the voice of rebuke ? 



93. To one who looks abroad to contemplate the agents of na- 

 ture, as he sees them at work upon our planet, no expression ut- 

 tered nor act performed by them is without meaning. By such an 

 one, the wind and rain, the vapor and the cloud, the tide, the cur- 

 rent, the saltness, and depth, and warmth, and color of the sea, the 

 shade of the sky, the temperature of the air, the tint and shape of 

 the clouds, the height of the tree on the shore, the size of its 

 leaves, the brilliancy of its flowers — each and all may be regarded 

 as the exponent of certain physical combinations, and therefore as 

 the expression in which Nature chooses to announce her own do- 

 ings, or, if we please, as the language in which she writes down 

 or chooses to make known her own laws. To understand that 

 language and to interpret aright those laws is the object of the 

 undertaking which we now have in hand. No fact gathered in 

 such a field as the one before us can, therefore, come amiss to 

 those who tread the walks of inductive philosophy ; for, in the 

 hand-book of nature, every such fact is a syllable ; and it is by pa- 

 tiently collecting fact after fact, and by joining together syllable 

 after syllable, that we may finally seek to read aright from the 

 great volume which the mariner at sea and the philosopher on the 

 mountain see spread out before them. 



94. Of its Circulation. — We have seen (M^) that there are 

 constant currents in the ocean ; we shall now see that there are 

 also regular currents in the atmosphere. 



95. From the parallel of about 30° north and south, nearly to 

 the equator, we have, extending entirely around the earth, two 

 zones of perpetual winds, viz., the zone of northeast trades on this 

 side, and of southeast on that. They blow perpetually, and are 



