Rules for the use of punctuation marks are very different from rules for the use of purely material things.

They are useless unless applied intelligently.

No set of rules could be devised which would work automatically or relieve the compositor from the necessity of thinking.

Punctuation can never be reduced to an exact science.
Certain general directions should be borne in mind by writers and printers.
I.Learn by heart the rules for punctuation.
II.

Note the peculiarities of the best writers and the best printers, especially in contemporary examples.
III.