296 MASSACHUSETTS AGRICULTURE. 



clicmical changes which are going on so continuously and vig- 

 orously around you and beneath your very feet. 



And what are these changes ? A knowledge of them teaches 

 the great secret of plant growth. It unfolds to us the philoso- 

 phy of that fact, incomprehensible to so many, how from the 

 ethereal atmosphere almost alone the solid forms of organized 

 structures are elaborated. 



How wonderful is this truth, gentlemen, that a large propor- 

 tion of the material of the grains, and fruits, and grasses, you 

 have just gathered into your barns and granaries, is composed 

 of the constituents of common air. Perhaps it is even more 

 wonderful, that the solid and inflexible fibres of the oak, the 

 hickory, the beech, and scores of other woods, exceeding even 

 these in density and hardness, are formed from the unstable 

 medium we breathe, and which seems so utterly devoid of ma- 

 teriality and solidity. 



Chemistry alone is capable of teaching the farmer the phi- 

 losophy of that aggregation of atoms, by which plant organisms 

 are developed and increased, until full maturity is attained. 

 It teaches him what office the soil, the rain and the air, sub- 

 serve in accomplishing the work, and the information it imparts 

 is minute, wonderfully exact and intensely interesting to the 

 student. It teaches him the interesting fact, that his soil orig- 

 inates from the solid rock which constitutes the crust of the 

 earth, and explains the nature of the forces which have pro- 

 duced crumbling and decay in the same. Its teachings are so 

 important in this particular that I will stop a moment to con- 

 sider them. 



If you procure from one of our hills a piece of granite of 

 either of the different varieties, and finely pulverize it and ana- 

 lyze it, you will find it to contain all the constituent elements 

 of which all othe»i' rocks consist. Hence, you will be led to 

 conclude that they all originate from the granite, that this is 

 the parent rock of quartz, talc, serpentine, feldspar, mica, &c., 

 from the crumbling of which our soils have been formed. By 

 the decomposition and crumbling of the mica and feldspar in a 

 particular region, one kind of soil is formed ; by limestone in 

 other localities, another kind ; and hence, it is plain to see that 

 a variety of soils must result from the disintegration of the dif- 

 ferent kinds of rocks. A very clear conception of the work of 



