In Avery v. Popper, 179 U.S. 305 (1900), the Supreme Court, speaking by Mr. Justice Brown, said: "With respect to writs of error from this court to judgments of state courts in actions between purchasers under judicial proceedings in the Federal courts and parties making adverse claims to the property sold, the true rule to be deduced from these authorities is this: That the writ will lie, if the validity or construction of the judgment of the Federal court, or the regularity of the proceedings under the execution, are assailed; but if it be admitted that the judgment was valid, and those proceedings were regular, that the purchaser took the title of the defendant in the execution, and the issue relates to the title to the property, as between the defendant in the execution or the purchaser under it, and the party making the adverse claim, no Federal question is presented - in other words, it must appear that the decision was made against a right claimed under Federal authority, in the language of Rev. Stat. 709." Again: "This was a question either of local law or of general law. If of local law, of course the decision of the Supreme Court of Texas is binding upon us. If of general law, as it involves no Federal element, it is equally binding in this proceeding, since only Federal rights are capable of being raised upon writs of error to state courts. Conceding that, if the question had arisen on appeal from a Circuit Court of the United States, we might have come to a different conclusion, it by no means follows that we can do so upon a writ of error to a state court, whose opinion upon a question of general law is not reviewable here."