THE ATMOSPHERE. 87' 



crystal vaults of the upper sky. Add to these the storm-king : 

 — traversing the air, he thrusts in the whirlwind or sends forth the 

 cyclone, the tornado, and the hurricane to stir up and agitate, to 

 mix and mingle the whole in one homogeneous mass. By this 

 perpetual stirring up, this continual agitation, motion, mixing, and 

 circulation, the airy covering of the globe is kept in that state 

 which the well-being of the organic world requires. Every breath 

 we draw, every fire we kindle, every blade of grass that grows or 

 decays, every blaze that shines and burns adds something that is 

 noxious, or takes something that is healthful away from the sur- 

 rounding air. Diligent, therefore, in their offices must the agents 

 be which have been appointed to maintain the chemical status of 

 the atmosphere, to presence its proportions, to adjust its ingredi- 

 ents, and to keep them in that state of admixtm'e best calculated to 

 fit it for its pur[)oses. 



237. Several years ago the French Academy sent out bottles 

 Experiments by the ^iid caused spccimcns of air from various parts of 

 Frei^ch Academy. j^]^q ^^orld to be collectcd and brought home to be 

 analyzed. The nicest tests Vv^hich the most skilful chemists could 

 apply were incapable of detecting any, the slightest, difference as 

 to ingredients m the specimens from either side of the equator ; 

 so thorough in the performance of then' office are these agents. 

 Nevertheless, there are a great many more demands on the atmo- 

 sphere by the organic world for loahuhiin in one hemisphere 

 than in the other ; and consequently a great many more inequali- 

 ties for these agents to restore in one than in the other. Of the 

 two, the land of our hemisphere most teems with life, and here 

 the atmosphere is most taxed. Here the hearthstone of the human* 

 family has been laid. Here, with our fires in winter and om- 

 crops in summer, with om- work-shops, steam-engines, and fiery 

 furnaces going night and day — with the ceaseless and almost 

 limitless demands which the animal and vegetable kingdoms are 

 making upon the air overhead, we cannot detect the slightest 

 difference between atmospherical ingredients in different hemi- 

 spheres ; and yet, notmthstanding the compensations and adjust- 

 ments between the two kingdoms of the organic world, there are 

 almost in every neighbourhood causes at work which would produce 

 a difference were it not for these ascending and descending columns 

 of air ; — were it not for the obedient winds, — for this benign system 

 of circulation, — these little cogs and ratchets which have been pro- 

 vided for its perfect working. The study of its mechanism is 



