76 THE YEAR. 



which both agencies are carried on ; though we are 

 not certain that the action may not depend upon some 

 component part of the atmosphere, unknown to our 

 observation or our instruments, and therefore without 

 a name in any vocabulary of rational philosophy. 



In so far, we know the chemical nature and the pro- 

 perties of the atmosphere ; we know that the greater 

 part of its mass is composed of two substances, in the 

 state of air or gas, which enter largely into the compo- 

 sition of natural bodies, both animate and inanimate ; 

 and we can eliminate them from their natural combi- 

 nations, and place them in artificial ones. 



The substances of which the ingenuity of modern 

 analysis has been able to detect the presence and de- 

 termine the proportions in the atmosphere, are nitrogen 

 and oxygen ; three fourths of the former to one fourth 

 of the latter by weight, and four fifths of the former to 

 one fifth of the latter by measure. There is also a 

 trace of carbonic acid, probably less than one part in a 

 thousand, upon the average. But we are not more 

 warranted in concluding that these substances form the 

 whole of that atmosphere which is the breath of life to 

 plants and animals, than we are in saying that a living 

 animal or vegetable is nothing more than the members 

 into which we can anatomise, or the substances into 

 which we can decompose a dead one. We know what 

 we discover in the analysis of the atmosphere, but we 

 do not know what we may lose in the process, or how 

 much of the active properties of the compound may 

 depend upon what we do lose. The energies of nature 

 have nothing to do with mass and magnitude ; one little 

 acorn will do more if you bury it in the earth than 



