10 
MANURES. 
stances found in plants is thus reduced from things 
which you did not know, to things which you do 
know; and so we have saved the trouble of learning 
more of their chemistry. 
We have reduced the airy or volatile into water, 
formed of oxygen and hydrogen; or volatile alkali, 
formed of nitrogen and hydrogen; or into acids, as 
the carbonic, formed of oxygen and carbon—as the 
sulphuric, formed of oxygen and sulphur—as the 
phosphoric, formed of oxygen and phosphorus; and 
having thus got water and acids, these unite with all 
the alkaline, earthy, and metallic bodies, and form 
salts. To give you new examples of these, I may 
mention Glauber’s salts and Epsom salts. Glauber’s 
salt is formed of soda and sulphuric acid; Epsom 
salts, of magnesia and sulphuric acid; alum, of 
alumina, or clay and sulphuric acid; green vitriol, of 
iron and sulphuric acid; white vitriol, of zinc and 
sulphuric acid; plaster of paris, of lime and sulphuric 
acid; bones, of lime and phosphoric acid; chalk and 
limestone, of lime and carbonic acid. These are all 
examples of salts ; that is, an acid, or a substance act¬ 
ing the part of an acid, united to an alkali, metal, or 
earth. 
ANALYSIS OF PLANTS. 
We have thus gone over, in a very general way, 
enough of chemistry for any one to understand the 
chemical nature of manure. You see, reader, that 
with common attention, bestowed for an evening’s 
reading, one may learn these chemical terms and their 
meaning. And now, having learned this first lesson, 
let us review the ground gone over, and fix, once and 
for all, these first principles in our minds. Let us do 
this, by a practical application of the knowledge we 
have gained. Let us analyze a plant. Do not be 
startled at the word. To analyze, means to separate 
a compound substance into the several substances 
