PREFACE, 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 toa 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 
