IMPORTANCE OP THE TOVR ORGAXIC ELEMENTS 13 



energy of the oxj'gen. Being incapable of burning 

 or supporting combustion, it prevents the general con- 

 flagration wiiich would occur in pure oxygen, and also 

 reduces its strength to the proper proportion for sus- 

 taining animal and \ ' ' ' ' 'in 

 any poisonoas or dt aer 

 gases would do. We see then that iu negative pro- 

 perties just fit it for its office. 



I have been thus particular in describing simple 

 processes for obtaining these gases, because every mind 

 is better satisfied by direct and practical proofs. The 

 experiments here criven are so easy that the most in- 

 (.\ ' ' ' rform them 



\\ of any size 



where the ii«i - terialh and apparatus can not 



be found, and i with little expense. Every 



teacher should illustrate his explanations by these 

 proofs; thereby impressing an idea of each substance 

 upon the mind more indelibly than could be done in 

 any other way. Many farmers could make them for 

 their own satisfaction in leisure hours. 



The reader will now underst ^ it is that I 



have urgtnl the ne<:essity of Ih-coi; uainted with 



these organic Ixxlies; for he has seen that they not 

 only compose by far the largft proportion of th« 

 vegetable world, but that mixtures of two or three of 

 them constitute the air we breathe, the water we drink, 

 »nd, in one shape or another, a large part of the earth 

 upon which we live. Are not these eminently bodies 

 with which all of every profi'ssion ought to be well 

 acquninte<I; and most of all the farmer, who depends 

 on them under rarious forms for all success, who can 

 not engage in the most simple operation without being 

 inflijenced by them in different and most important 

 ways? The man who knows the principal properties 

 ami the peculiar energies of the materials with which 



