DEVELOPMENT. tl 



plow, which do the work of a dozen old-fashioned 

 implements. The sickle has given place to the cra- 

 dle, the cradle to the reaper, the scythe to the mower, 

 the old tedious process of separating cotton-seed 

 from the fiber by hand, to the cotton-gin, and a great 

 many other mechanical improvements which the in- 

 ventive genius of the nineteenth century has given 

 to the world. 



10. Among the benefits derived from chemistry 

 may be mentioned : 



1. It teaches the composition and qualities of 

 soils, of plants, of the atmosphere, of fertilizers. 



2. It determines the kind and quality of food 

 that different plants need for strong, healthy growth. 



3. It shows how to manufacture fertilizers, and to 

 make use of all sorts of refuse matter in the prepara- 

 tion of food for plants. 



4. It explains the action of light, heat, and other 

 agencies in promoting growth, and, in a word, un- 

 folds all the conditions of fertility. 



IT. The chemist in his investigations proceeds 

 to analyze the soil, and plant, and air, and fertilizers, 

 that he may understand their nature and the rela- 

 tions they sustain to each other ; and we propose to 

 inquire into the results of these investigations, and 

 show in few words what modern science teaches of 

 the composition and use of these substances with 

 which the farmer and planter have so much to do. 



