[1] Public Lands—Erroneous Issuance of Patent — Legal Mistake of Department Officials—Trust.—If, through a mistake of law on the part of the officials of the Department of the Interior, a patent to land to which one person is entitled under the public land laws erroneously issues to another, the latter will be held by the courts to hold the legal title received from the government in trust for him who should have received it.

[2] Id.—Function of Department Regulations. — The function of Land Department regulations is to carry out the purpose of the statute for whose administration they are adopted, and they must be reasonable and appropriate for such purpose and cannot either enlarge or impair a right given by the statute.

[3] Id.—When Regulations Void.—If the meaning of a statute relating to public lands be doubtful, the construction put upon it by the administrative officers should be given great weight by the courts in determining its true meaning, but if its meaning be not doubtful and the regulations are in conflict with that meaning, they are simply void.

[4] Id.—Purchase of Lots Between Resurveyed Government Subdivisions — Preferred Rights of Abutting Owners — Construction of Act of Congress.—The act of Congress providing that any land owner or entryman whose land adjoined any lot should have a preferred right to purchase the one-half of the lot which abutted on his land (35 Stats, at Large, 779), must be given effect as far as possible, and the fact that it may not be possible to give it effect in one class of Cases is no reason for not giving it effect in other cases where it is possible.

[5] Id.-—Lots Abutting upon Lands of More Than One Owner.— .Under such act, each land owner has the preferred right to purchase the one-half of any lot on his side which is in front of or abuts upon his land, and where a lot abuts on one side on the lands of more than one owner, each owner has the preferred right of purchase of the portion of such one-half which is in front of or abuts upon his land.