That certain words are prepositions, there can be no doubt, because the
books say they are; but _why_ they are so, is quite another matter. All
we desire is to have their meaning understood. Little difficulty will
then be found in determining their use.

I have said they are derived from verbs, many of which are obsolete.
Some are still in use, both as verbs and nouns. Take for example the
word =with=. This word signifies _joined_ or _united_. It is used to
show that two things are some how joined together so that they are spoke
of in connexion. It frequently occurs in common conversation, as a verb
and noun, but not as frequently in the books as formerly. The farmer
says to his _hired_ man, "Go and get a _withe_ and come and _withe_ up
the fence;" that is, get some pliant twigs of tough wood, twist them
together, and _withe_ or bind them round these posts, so that one may
stand firm _with_, or _withed_ to, the other. A book _with_ a cover, is
one that has a cover _joined_, bound, or attached to it. "A father
_with_ a son, a man _with_ an estate, a nation _with_ a constitution."
In all such cases _with_ expresses the relation between the two things
mentioned, produced by a _union_ or connexion with each other.[6]

=In= is used in the same way. It is still retained as a noun and is
suspended on the signs of many public houses. "The traveller's _inn_,"
is a house where travellers _in_ themselves, or go _in_, for
entertainment. It occurs frequently in Shakspeare and in more modern
writers, as a verb, and is still used in common conversation as an
imperative. "Go, _in_ the crops of grain." "_In_ with you." "_In_ with
it." In describes one thing by its relation to another, which is the
business of adjectives. It admits of the regular degrees of comparison;
as, _in_, _inner_, _innermost_ or _inmost_. It also has its compounds.
_In_step, the _inner_ part of the foot, _in_let, _in_vestment,