As has been already explained in the Accidence the greater number of
these words in Finnish are declinable substantives, and take the various
cases under just the same rules as an ordinary noun. With the exception
of a certain number of petrified and isolated forms, they may be compared
to the word _midst_ in English. We say _he came from the midst_, _went
into the midst_, or _stood in the midst_. In the language of Finnish
grammarians such forms would be considered as adverbs. Whereas in such
expressions as _in the midst_, or _from the midst of the crowd_, they
would be called postpositions or prepositions. This practice of declining
adverbs and postpositions is, however, carried to lengths for which no
analogy can be found in English. Thus =myöhä=, is _late_ (an adjective),
but _to come late_ is rendered by =tulla myöhään=; on account of the idea
of motion in the verb. _To watch late into the night_ is =valvoa myöhälle
yötä=, and such an expression as _later on_ (of a date) is rendered by
the essive =myöhempänä=.
Most, but not all, postpositions, are capable of taking the pronominal
affixes, with or without a genitive of the personal pronoun before them.
The subjoined list of prepositions and postpositions gives all the words
considered as falling under these categories by ordinary grammars. As a
matter of fact, it might very well be either enlarged or curtailed, which
last would be better, as some of the words are substantives in ordinary
use. But I have thought it better to adhere to the conventional list.