The measurements of the corresponding letters in twelve genuine signatures are shown in the table as Examples 1 to 12.
The total is averaged by dividing by twelve.
The presumption in favour of the suspected signature being a forgery is strongly supported by the arithmetical result.
A difference of more than 2 per cent. in angle of slope, and 3 per cent. in height may be safely relied upon as ground for suspicion, for it is rarely that a man's signature varies so greatly within a brief period. In the absence of the explanation provided by illness, intentional change in style or other abnormal circumstances, such a difference as is shown in this example will justify a belief that the suspected signature is by another hand.
| Height in lines. | Angle of slope. | ||||||||
| B. | l. | k. | b. | B. | l. | k. | b. | ||
| Forgery | ... | 7 | 7 | 6 | 7¼ | 15 | 20 | 21 | 21 |
| Example | 1 | 7¼ | 6½ | 5½ | 7½ | 16 | 22 | 21 | 20 |
| " | 2 | 7¼ | 6¼ | 6 | 7¼ | 17 | 21 | 20 | 20 |
| " | 3 | 7¼ | 6 | 5¾ | 7¾ | 16 | 21 | 20 | 21 |
| " | 4 | 7 | 6¼ | 5¾ | 7½ | 16 | 21 | 20 | 21 |
| " | 5 | 7 | 6¾ | 5¾ | 7½ | 17 | 22 | 21 | 20 |
| " | 6 | 7½ | 6¾ | 5 | 7½ | 16 | 21 | 20 | 21 |
| " | 7 | 7½ | 6 | 6 | 7¼ | 17 | 20 | 21 | 21 |
| " | 8 | 7½ | 6½ | 5¾ | 7½ | 16 | 22 | 21 | 21 |
| " | 9 | 7¼ | 6½ | 5½ | 7 | 16 | 21 | 21 | 21 |
| " | 10 | 6¾ | 6½ | 5¾ | 7¼ | 16 | 20 | 21 | 21 |
| " | 11 | 7¼ | 6¾ | 5¾ | 7½ | 16 | 21 | 21 | 22 |
| " | 12 | 7 | 6¼ | 5¾ | 7½ | 16 | 20 | 21 | 21 |
| Average | ... | 7¼ | 6½ | 5¾ | 7½ | 16¼ | 21 | 20¾ | 20¾ |
CHAPTER III.
Terminology.
