his detection certain.

Since typewriting has come so generally into use, the question often
arises as to the identity of typewriting by different operators as
well as that done on different machines. This may usually be done with
considerable degree of certainty. Different operators have their own
peculiar methods, which differ widely in many respects,--in the
mechanical arrangement, as to location of date, address, margins,
punctuation, spacing, signing, as well as impression from touch, etc.

The distinctive character of the writing done on different machines is
usually determined with absolute certainty. With most machines there
are accidental variations in alignment. Certain letters from use
become more or less imperfect, or become filled or fouled with ink. It
is highly improbable that any one even of these accidents should occur
in precisely the same way upon two machines, and that any two or more
should do so is well nigh impossible. It is equally certain that all
the habits and mannerisms of the operators would not be precisely the
same. A careful comparison of different typewritings in these respects
cannot fail to determine whether they are written by the same operator
or upon the same machine. It should be remembered that writing upon
the same machine will differ in all the respects mentioned at
different stages of its use and condition.

An immaterial alteration is one which does not change the legal effect
or significance of an instrument. If what has been written upon or
erased from the instrument has no tendency to mislead any person to
the instrument, it will not be an alteration; it is immaterial also
where the meaning is in no manner varied or changed.