II 



elements, known to exist, we fincJ vegetables almost entirely 

 composefl of three, viz. charcoal and two gases. A few others are 

 occasionally present, and in some cases seem essential to the con- 

 stitution of the plant; such assilex, lime, iron, manganese, &.c. 

 It is by variously combining these few elements that the numerous 

 proximate principles of vegetables, such as sugar, gum, starch, 

 and the like, are produced; and also the unnumbered forms and 

 properties of the stalk, the bark, the wood, the leaves, the roots, 

 the flowers, and the fruit. A beautiful example of the simplicity 

 of nature ! 



The next point on which chemistry affords light to the agri- 

 culturist, is the composition of the soil and atmosphere in which 

 plants are placed. That they derive their nourishment from the 

 tirst, if not the second of these sources, is certain. It is necessa- 

 ry, therefore, that in these, should be found all those simple sub- 

 stances that are essential to the constitution of vegetables ; and 

 the whole subject of manures consists of little else than an ac- 

 count of the modes in which these principles are supplied. The 

 analysis of the soil will show which, if any, is deficient ; and thus 

 point to the best mode of supplying those that are wanting. 



In regard to those changes that the sap of plants undergoes 

 before it is converted into the vegetable itself, and its various 

 peculiar principles, upon these changes, although entirely 

 chemical, chemistry sheds but a feeble light. We know that 

 every plant must be a perfect laboratory ; for we see the sap, 

 which is nothing more than water, holding a few things in solu- 

 tion, entering the vessels of the vegetable, and having passed 

 through them, we find a most wonderful conversion of this sap 

 into pith, wood, bark, leaves, flowers, fruit, and numerous pecu- 

 liar and compound products; such as gum, sugar, acid, and the 

 like. Here is proof that the most complicated and delicate 

 chemical processes are continually going on in all living plants ; 

 processes that infinitely exceed the skill of the most accomplish- 

 ed chemist ; and yet, they are hid, from even microscopic obser- 

 vation, by the minuteness of the vessels and agents concerned. 

 We know only that a certain degree of heat and moisture are re- 

 quisite, and sometimes light also, to carry forward the operation. 



