Of what use are the two remaining substances, Hydrogen and Carbon?

These are appropriated by the vegetative organs to their growth and
nourishment, while the oxygen with which the carbon was combined is
abundantly given off to purify the air and render it fit for the
respiration of animals.


Give me an idea of the mode in which Chemists ascertain the _affinity_
of bodies, by relating an experiment.

Dissolve a tea-spoonful of sugar of lead in water, and pour the clear
solution into a decanter or large glass bottle. Then take a small
piece of zinc, and twist round it some brass or copper wire, so as to
let the ends of the wire depend from it in any agreeable form. Suspend
the zinc and wire in the solution which has been prepared; in a short
time, metallic lead will deposit itself on the zinc and along the
wire. This is a beautiful illustration of chemical affinity; the acid,
which constitutes a part of the sugar of lead, has a stronger affinity
for the zinc than for the lead, and, consequently, will combine with
the zinc, and form a compound which remains in solution, while the
lead is precipitated on the zinc and wire in the form of a brilliant
tree of metal.

_Affinity_, in chemistry, that attraction which takes place
between the elements of bodies, and forms compounds.


What does the word Nature signify?