一D格言既grammar!

of and oft
(1)
"by of falling' or 'by of something" is incorrect by any standard of grammar.
The "grammatical mistake" perceived by you is a result of the misprint in your quotation in which 'oft' was taken as 'of', thus causing your concern.
The English translation of original saying by Lucretius is like this:
"The drops of rain make a hole in the stone, not by violence, but by oft falling."
'Oft' is the short form of 'often'. "oft falling" means falling many times.
(2)
"of something" itself means "composed or made from something". Therefore "a house of stone" already has the meaning of " a house made of stone". It is a correct expression.




2013-06-12 16:58:42 補充：
Similarly, "The house is of stone " has the meaning of " The house is made of stone" although it is more common to say " The house is of stone construction".

Some proverbs in Grammar may be "Inversion":-
eg:-By falling the rain drops a hole.
eg:-Rain drops a hole by falling.
where altering the natural order of words are found;
It may also be a participle phrase containing a gerund:-
eg:-the gerund phrase=by falling.
Error and correction:-
This house is of stone-built. meaning stones used by builders;
eg:-of stone-built is a prepositional phrase qualifying "house".
eg:-"of stone-built" is placed after the verb "is"
eg:-The house is made of stones=kinds of stone,may be rock, boulder, cobble, gravel, pebble etc.