If, then, the court of one State in determining the legal effect of a transaction having its seat in another must be governed by the common law of that State, where is it to be found? If there have been decisions of its highest courts in regard to what it is with reference to the point in question, they will ordinarily be accepted as conclusive. This is not by virtue of the provision in the Constitution of the United States that full faith and credit is to be given in each State to the public records and proceedings of the others. That refers to the effect of public records and proceedings upon the rights of those who are or claim under parties to them. Such decisions as those which have been described are accepted as conclusive as to the rights of those who were not parties to them, and simply because they are considered the best evidence attainable of a rule of unwritten law of general application. But they are not universally so considered. The rule that transactions are governed by the law of the place where they have their seat is one founded on the presumed intent of the parties to them. But in fact the parties to a business transaction act on their general notions of what the law is or must be, rather than on any particular knowledge of what courts have declared that it is. The rule that one country will accept the opinion of the judicial authorities of another as to what its law is, is one not to be pressed so far as to sacrifice essential justice. In this point of view, some courts hold that it is permissible to disregard decisions of other States which are based on a departure from what is generally considered a settled doctrine of the common law as to a commercial question. This is substantially the same position taken by the Supreme Court of the United States, and elsewhere described,[Footnote: See Chap. X.] concerning the right of a federal court to refuse to be bound by State decisions as to the unwritten law affecting foreign trade or trade between the States.[Footnote: Faulkner _v._ Hart, 82 N. Y. Reports, 413, 423.] Another rule of practice of great importance is that in the absence of proof to the contrary the courts will presume, in a State basing its jurisprudence on the English common law, that the unwritten law of any other American State is the same as its own. As the reason of this rule fails in the case of Louisiana, Florida and Texas, which were subject to organized governments not derived from Great Britain at the time when they were incorporated into the United States, it is not applied to them.[Footnote: Norris _v._ Harris, 15 California Reports, 253.]