PKEFACE. V 



of his acquaintance with them. Such facts are not, how- 

 ever, for this reason to be ignored or refused a place in our 

 treatise, nor do they render our book less practical or less 

 valuable. It is just such curious and seemingly useless 

 facts that are often the seeds of vast advances in industry 

 and arts. 



For those who have not enjoyed the advantages of the 

 schools, the author has sought to unfold his subjects by 

 such regular and simple steps, that any one may easily 

 master them. It has also been attempted to adapt the 

 work in form and contents to the wants of the class-room 

 by a strictly systematic arrangement of topics, and by di- 

 vision of the matter into convenient paragraphs. 



To aid the student who has access to a chemical labor- 

 atory and desires to make himself practically familiar 

 with the elements and compounds that exist in plants, a 

 number of simple experiments are described somewhat in 

 detail. The repetition of these will be found extremely 

 useful by giving the learner an opportunity of sharpening 

 his perceptive powers, as well as of deepening the impres- 

 sions of study. 



The author has endeavored to make this volume com- 

 plete in itself, and for that purpose has introduced a short 

 section on The Food of the Plant. In the succeeding vol- 

 ume, which is nearly ready for the printer, to be entitled 

 " How Crops Feed," this subject will be amplified in all 

 its details, and the atmosphere and the soil will be fully 

 discussed in their manifold Relations to the Plant. A 

 third volume, it is hoped, will be prepared at an early day 

 upon Cultivation; or, the Improvement of the Soil and the 

 Crop by Tillage and Manures. Lastly, if time and 

 strength do not fail, a fourth work on Stock Feeding and 

 Dairy Produce, considered from the point of view of 

 chemical and physiological science, may finish the series. 



It is a source of deep and continual regret to the writer 

 that his efforts in the field of agriculture have been mostly 



