is la oc i 
eee et 
+ 
- other ‘ety could they have been more beneficially directed ? 
Wi herefore insist upon the utility of such works as the 
Agricultural Cheap of Liebig, and the still more practical treatise 
of Prof. Johnston. The latter is addressed, not to the philosopher, nor 
the student, but to the tiller of the soil himself. It consists of a series 
of lectures, delivered before a society of practical a agriculturists ; most 
of whom doubtless possess little or no knowledge of chemistry or 
geology. It was therefore necessary to begin with the simplest facts 
and principles of these sciences, to em employ the most familiar illustra- 
previous explanation. In pursuance of this plan, Prof. Johnston has 
_ produced a work of the most interesting and popular character, com- 
pletely adapted to the end in view, and fully worthy of his reputation as 
achemist. The first part of these lectures, the only portion which has 
yet been issued in this country, is devoted to a consideration of the 
organic elements and parts of plants, the properties of the elementary 
and compound bodies which enter into their substance, or contribute to 
their growth and nourishment; to the general structure and uses of the 
several parts of plants; their mode of growth, and the manner in which 
rai absorbed and assimilated. 
~The second part, which we understand will soon appear, is to be dee 
voted to the inorganic elements of plants, and to the study of the soils 
from which these are derived; the constitution, origin, and methods of 
improving soils in different districts, and under unlike conditions, with 
the general relations of geology to agriculture.. The third, to the na- 
ture of manures, their mode of action, &c.: the fourth and last, to the 
results of vegetation, the nature, constitution, and nutritive properties 
of different kinds of produce, especially in reference to their several 
equivalents or powers of supporting animal life ; the feeding of cattle, 
the making of cheese, &c.; the constitution and differences of various 
_ kinds of wood, and the cipcqmmtintica which favor their growth. After 
this general view of the plan and scope of the work, we think it quite 
‘Unnecessary to give an analysis of the eight lectures of which the pres- 
ent portion is composed. In the first lecture, which is chiefly prelimi- 
hary, the author bestows a few thoughts upon the importance of agri- 
s “culture : 
'. “ That art on which a thousand millions of men are dependent for their very sus- 
' in the prosecution of which nine tenths of the fixed capital of all civili- 
zed nations is embarked—and probably two hundred millions of men expend their 
daily toil—that art must confessedly be the most important of all ; the parent and 
precursor of all other arts. In every country then, and at every gexied, the inves- 
Ss _ Bention of the principles on which the rational practice of this art is founded, 
‘to have commanded the principal attention of the greatest minds. 
of every country when the study of agriculture 
