Supreme court of the United States. No. 135. The United States, appellants, vs. John A. Sutter. Appeal from the District court U.S. for the Northern district of California.

124 The United States vs. Sutter.
from our observation,in numerous cases which have come before
us, that it was a frequent custom of the Mexican authorities to annex
certified copies of the maps contained in the espediente to such grants
as had reference to them, for greater certainty of description, and in
some cases the original map, instead of being filed with the espediente,
was attached to the title, and delivered with it to the grantee. The
grant to Captain Sutter was in the nature of an empresario grant, and
contemplated side grants from him to his settlers; it is therefore a
most reasonable inference to suppose that either the original map,
or a copy of it, would be delivered with the grant, in order to enable
him to satisfy them as the limits within which he was authorized
to make settlements and sub-alienations.. Capt. Vioget's survey and
map were made a few months before Capt. Sutter applied for his
grant, and it is a legitimate presumption to suppose that the survey
was made preparatory to that -application, and that the map founded
upon it was intended as the one with which, under the law, he was
required to accompany his petition. This presumption is greatly
strengthened by the fact that the objects and lines delineated on the
map correspond, in all material respects, with the words of description
contained in the grant. Taking these circumstances in connection
with the testimony of Fowler, who identifies the paper marked Exhibit B as a true copy of the map which he found attached to the
original grant in 1850, and that of Vioget, who proves the same paper
to be substantially a correct copy of the one made by him in 1841,
we are led to the conclusion, with a moral certainty approaching to
demonstration, that the map executed by Vioget was the one which
accompanied the petition of Sutter for the grant, and which is referred to in that instrument; and that the paper marked Exhibit B is,
in all essential particulars, a true copy of the same, and as such is
admissible in evidence for the purpose of locating and identifying the
lands claimed under the grant.
159 Admitting, then, the map in question as competent testimony
for this purpose, we will now proceed to consider the evidence
on this point, in connexion with the well-settled principles of law which
control in disputed questions of locations and boundaries. The first
of these to which we will revert is, as to the admissibility of parol
proof to explain written instruments.
The doctrine laid down by law agent, that parol testimony cannot
be introduced to vary the language of a written instrument, or supply
a defect, is unquestionably true, but it is equally true that such testimony may be adduced to ascertain the meaning and intent of the language used, and in what maner the terms of the instrument affect the
property or subject-matter. In this view, evidence is admissible of
all the circumstances surrounding the author of the instrument all the
time of its execution. Thus, if the language of the instrument is applicable to several persons, to several parcels of land, to several
monuments or boundaries, &c., evidence is admissible of extrinsic
circumstances, tending to show what persons, what lands, or what
boundaries or monuments were intended by the party, or to ascertain
his meaning in any other respect; the rule only excluding parol evi: