from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
LETTERS ROGATORY. A letter rogatory is an instrument sent in the name and by
the authority of a judge or court to another, requesting the latter to cause
to be examined, upon interrogatories filed in a cause depending before the
former, a witness who is within the jurisdiction of the judge or court to
whom such letters are addressed. In letters rogatory there is always an
offer on the part of the court whence they issued, to render a similar
service to the court to which they may be directed whenever required. Pet.
C. C. Rep. 236.
2. Though formerly used in England in the courts of common law, 1 Roll.
Ab. 530, pl. 13, they have been superseded by commissions of Dedimus
potestatem, which are considered to be but a feeble substitute. Dunl. Pr.
223, n.; Hall's Ad. Pr. 37. The courts of admiralty use these letters, which
are derived from the civil law, and are recognized by the law of nations.
See Foelix, Dr. Intern. liv. 2, t. 4, p. 800; Denisart, h.t.