from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
SUBSCRIBING WITNESS. One who subscribes his name to a writing in order to be
able at a future time to prove its due execution; an attesting witness.
2. In order to make a good subscribing witness, it is requisite he
Should sign his name to the instrument himself, at the time of its
execution, and at the request or with the assent of the party. 6 Hill, N. Y.
R. 303; 11 M. & W. 168; 1 Greenl. Ev. Sec. 569 a, 4th ed. See Witness
instrumentary; 5 Watts, 399.