ve become mechanical acts, done
without thought or premeditation, but as the result of a long-formed
habit.

It is these unconscious hand-gestures and mechanical tricks of style
that the handwriting expert learns to distinguish and recognise,--the
unconsidered trifles that the writer has probably never devoted a
minute's thought to, and which come upon him as a surprise when they are
pointed out to him. Their detection is rendered the more easy when one
knows what to look for from the fact that they are, unlike gestures and
tricks of voice, permanent. A mannerism may not strike two observers in
the same way, nor is it easy to compare, for it is fleeting, and the
memory has to be relied upon to recall a former gesture in order to
compare it with the last. It is not so with a hand-gesture in writing.
The sign remains side by side with its repetition, for careful and
deliberate comparison; and if the writing be a long one, the expert has
the advantage of being in possession of ample material on which to base
his judgment.

_A Popular Fallacy._--One of the most frequent objections offered by the
casual critic when the subject of expert testimony is discussed is to
the effect that people write different hands with different pens, and he
probably believes this to be true. A very slight acquaintance with the
principles on which the expert works would satisfy this spontaneous
critic of the fallacy of his objection. A person who habitually writes a
fine, small hand, sloping from right to left, may believe that he has
altered the character of his hand by using a thick, soft quill,
reversing the slope to what is called a backhand, and doubling the size
of the letters. All he has done is to put on a different suit of
clothes; the same man is in them. The use of a thick pen does not make
him put a dot over the _i_ where before he made an horizontal dash; it
does not turn a straight, barred _t_ into a curved loop, neither does it
alter the proportionate distance between the letters and lines. It does
not make him form loops where before he habitually made bars, or _vice
versa_, and if he formerly made a _u_ with an angle like a _v_ he will
not write the _u_ with a rounded hook. Neither will it cause him to drop
his habit of adding a spur to his initial letters or curtail the ends
and tails that he was wont to make long. In short, the points to which
the expert devotes his investigation are those least affected by any
variation in t