INTRODUCTION. 27 



heat, light, and other agencies, is annulled or overcome, so 

 that compounds resolve themselves into simpler combina- 

 tions or into their elements. Chemistry is the science of 

 composition and decomposition ; it considers the laws and 

 results of affinity. 



III. Physiology, which unfolds the laws of the devel- 

 opment, sustenance, and death, of living organisms. 



When we assert that the object of agriculture is to de- 

 velop from the soil the greatest possible amount of cer- 

 tain kinds of vegetable and animal produce at the least 

 cost, we suggest the topics which are most important for 

 the agriculturist to understand. 



The farmer deals with the plant, with the soil, with ma- 

 nures. These stand in close relations to each other, and 

 to the atmosphere which constantly surrounds and acts 

 upon them. How the plant grows, the conditions under 

 which it nourishes or suffers detriment, the materials 

 of which it is made, the mode of its construction and 

 organization, how it feeds upon the soil and air, how it 

 serves as food to animals, how the air, soil, plant, and 

 animal, stand related to each other in a perpetual round 

 of the most beautiful and wonderful transformations, 

 these are some of the grand questions that come before 

 us ; and they are not less interesting to the philosopher 

 or man of culture, than important to the farmer who 

 depends upon their practical solution for his comfort ; or 

 to the statesman, who regards them in their bearings 

 upon the weightiest of political considerations. 



