CHYMISTRY APPLIED TO AGRICULTURE, 3 



The specific gravity of oxygen is to that of the atmo- 

 sphere, as 11,036 to 10,000. The effects produced by ox- 

 ygen are equally numerous and important; it supports 

 animal life by respiration ; and combining with the carbon 

 of the blood, it produces the greatest proportion of animal 

 heat. The germination of seeds is promoted by this gas, 

 and it is absorbed by the leaves of plants during the 

 night : by its combination with the metals the oxides of 

 them are formed. It is likewise the necessary agent of 

 combustion, and concurs powerfully in the decomposition 

 of all animal, vegetable, and mineral substances. 



In all cases where oxygen exerts its action, it combines 

 with some one of the elements upon which it acts, forming 

 acids with carbon, azote, sulphur, phosphorus, and many 

 of the metals ; water with hydrogen, 6lc. The nature of 

 the compositions, of which oxygen is an element, varies 

 according to the proportions in which it enters into com- 

 bination. 



When we survey the extent and importance of the ope- 

 rations performed by this gas, and especially when we 

 consider that it is constantly forming new bodies, with 

 which it afterwards ceases to have any connexion, we are 

 almost led to fear, that the atmosphere must be^ sooner or 

 iater, exhausted of this active and regenerating principle ; 

 but nature, we find, is continually repairing the loss thus 

 sustained, by the production of equivalent quantities. The 

 leaves of plants, under the influence of the solar rays, 

 pour forth into the atmosphere torrents of oxygen, pro- 

 duced by the decomposition of carbonic acid and of water ; 

 of which they appropriate to themselves the carbon and 

 the hydrogen. 



It is without doubt possible, that in many situations the 

 reproduction of oxygen is not in proportion to its con- 

 sumption. This must happen especially where great quan- 

 tities are required for respiration, or to support combus- 

 tion. But this deficiency is only partial and momentary ; 

 for the great mobility of the atmospheric fluid enables it, 

 almost immediately, to restore its equilibrium from all 

 points. The agitation of the winds mixes together, ia 

 proportions nearly constant, both the elements of which 

 the atmosphere is composed, and the principal fluids 

 which are found in it. 



The creation or destruction of any element is not to be 

 found in the operations of nature. The numerous ph« 



