In Boardman v. Lessees of Reed (1832) 31 U.S. 328, it was held that the entire description of the lands given in a patent must be taken together, and the identity of the land ascertained by a reasonable construction of the language used; but if there be a repugnant call, which by the other calls of the patent clearly appears to have been made through mistake, that does not make the patent void; that to explain an ambiguity or doubt which arises from a certain call in the patent, the call may be explained either by showing that it was made through mistake, or that under the circumstances which existed at the time of the survey of the land patented, it was not inconsistent with the other calls of the patent; that the meaning of the parties to a patent for land must be ascertained, like that of all written instruments, by the terms of the whole patent, and not by looking at a part of it, and that if a latent ambiguity arise from the language used, it may be explained by parol. The Court said: "That boundaries may be proved by hearsay testimony is a rule well settled; and the necessity or propriety of which is not now questioned. Some difference of opinion may exist as to the application of this rule, but there can be none as to its legal force. Landmarks are frequently formed of perishable materials. . . . By the improvement of the country, and from other causes, they are often destroyed. It is therefore important, in many cases, that hearsay or reputation should be received to establish ancient boundaries." This was a case of private boundaries purely, and the declarations were rejected not upon the ground of hearsay, but because they were considered as immaterial, and not tending to elucidate any question before the jury. McLean, J. said: "That when an individual claims land under a tax sale, he must show that the substantial requisites of the law have been observed; but this is never necessary when the claim rests on a patent from the commonwealth."