pin draw bar. It was the duty of the jury to pass upon this conflicting evidence, and it was the duty of the presiding judge to instruct the jury clearly as to the duty imposed upon the defendant by the act of Congress. Before passing to the consideration of the charge to the jury we will for ourselves determine the meaning of that act. We think that it requires that the center of the draw bars of freight cars used on standard gauge railroads shall be, when the cars are empty, thirtyfour and one-half inches above the level of the tops of the rails; that it permits, when a car is partly or fully loaded, a variation in the height downward, in no case to exceed three inches; that it does not require that the variation shall be in proportion to the load, nor that a fully loaded car shall exhaust the full three inches of the maximum permissible variation and bring its draw bars down to the height of thirty-one and onehalf inches above the rails. If a car, when unloaded, has its draw bars thirty-four and one-half inches above the rails, and, in any stage of loading, does not lower its draw bars more than three inches, it complies with the requirements of the law. If, when unloaded, its draw bars are of greater or less height than the standard prescribed by the law, or if, when wholly or partially loaded, its draw bars are lowered more than the maximum variation permitted, the car does not comply with the requirements of the law. On this aspect of the case the presiding judge gave certain instructions and refused certain instructions, both under the exception of the defendant. The jury were instructed, the italics being ours:

"I. The act of Congress fixes the standard height of loaded cars engaged in interstate commerce on standard gauge railroads at thirty-one and one-half inches, and unloaded cars at thirty-four and one-half inches measured perpendicularly from the level of the face of the rails to the centers of the draw bars, and this variation of three inches in height is intended to allow for the difference in height caused by loading the car to the full capacity, or by loading it partially, or by its being carried in the train when it is empty. Now, the law required VOL. CCX-19

that the two cars between which Taylor lost his life should be when unloaded of the equal and uniform height from the level of the face of the rails to the center of the draw bars of thirtyfour and one-half inches, and when loaded to the full capacity should be of the uniform height of thirty-one and one-half inches. Now, if the plaintiff by a preponderance of the evidence shows a violation of this duty on part of defendant, then this is negligence, and if the proof by a preponderance also shows that this caused or contributed to the death of Taylor, then you should find for the plaintiff, unless it appears by a preponderance of the evidence that Taylor was wanting in ordinary care for his own safety, and that this want of care on Taylor's part for his own safety caused or contributed to the injury and death sued for, in which latter case you should find for the defendant.

"II. If there was the difference between the height of the center of the draw bars in the two cars in question, as indicated in the first instruction, then the question arises whether this difference caused or contributed to the injury and death of Taylor sued for. On that point if such difference existed, and but for its existence the injury and death of Taylor would not have happened, then such difference is said in law to be an efficient proximate cause of Taylor's injury and death, although it may be true that other causes may have coöperated with this one in producing the injury and death of Taylor, and but for these other coöperating causes the injury and death of Taylor would not have ensued. But if such difference in height of the center of the draw bars as aforesaid actually existed, yet if the injury and death of Taylor would have ensued just the same as it did without the existence of such difference in height of the center of the draw bars, then such difference in the height of the center of the draw bars is not in law an efficient proximate cause of the injury and death of Taylor."

The clear intendment of these instructions was that the law required that the draw bars of a fully loaded car should be of the height of thirty-one and one-half inches, and that if either of the cars varied from this requirement the defendant had

failed in the performance of its duty. We find nothing in the remainder of the charge which qualifies this instruction, and we think it was erroneous. We should be reluctant to insist upon mere academic accuracy of instructions to a jury. But how vitally this error affected the defendant is demonstrated by the fact that its own evidence showed that the draw bar of the fully loaded car was thirty-two and one-half inches in height. Under these instructions the plaintiff was permitted. to recover on proof of this fact alone. From such proof a verdict for the plaintiff would logically follow. The error of the charge was emphasized by the refusal to instruct the jury, as requested by the defendant, "that when one car is fully loaded and another car in the same train is only partially loaded, the law allows a variation of full three inches between the center of the draw bars of such cars, without regard to the amount of weight in the partially loaded car." This request, taken in connection with the instruction that the draw bars of unloaded cars should be of the height prescribed by the act, expressed the true rule, and should have been given. On the other hand, a request for instructions, which was as follows, "The court charges you that the act of Congress allows a variation in height of three inches between the centers of the draw bars of all cars used in interstate commerce, regardless of whether they are loaded or empty, the measurement of such height to be made perpendicularly from the top of the rail to the center of the draw bar shank or draft line," contained an erroneous expression of the law, and was correctly refused. It is based upon the theory that the height of the draw bars of unloaded cars may vary three inches, while the act, as we have said, requires that the height of the draw bars of unloaded cars shall be uniform.

But we have not the power to correct mere errors in the trials in state courts, although affirmed by the highest state courts. This court is not a general court of appeals, with the general right to review the decisions of state courts. We may only inquire whether there has been error committed in the

decision of those Federal questions which are set forth in § 709 of the Revised Statutes, and it is strenuously urged that the error in this part of the case was not in the decision of any such Federal question. That position we proceed to examine. The judicial power of the United States extends "to all cases, in law and equity, arising under this Constitution, the laws of the United States, and treaties made, or which shall be made, under their authority." Article III, § 2, Constitution. The case at bar, where the right of action was based solely upon an act of Congress, assuredly was a case "arising under the laws of the United States." It was settled, once for all time, in Cohens v. Virginia, 6 Wheat. 264, that the appellate jurisdiction, authorized by the Constitution to be exercised by this court, warrants it in reviewing the judgments of state courts so far as they pass upon a law of the United States. It was said in that case (p. 416): "They [the words of the Constitution] give to the Supreme Court appellate jurisdiction in all cases arising under the Constitution, laws, and treaties of the United States. The words are broad enough to comprehend all cases of this description, in whatever court they may be decided;" and it was further said (p. 379): "A case in law or equity consists of the right of the one party, as well as of the other, and may truly be said to arise under the Constitution or a law of the United States, whenever its correct decision depends on the construction of either." But the appellate jurisdiction of this court must be exercised "with such exceptions and under such regulations as the Congress shall make." Article III, § 4, Constitution. Congress has regulated and limited the appellate jurisdiction of this court over the state courts by § 709 of the Revised Statutes, and our jurisdiction in this respect extends only to the cases there enumerated, even though a wider jurisdiction might be permitted by the constitutional grant of power. Murdock v. Memphis, 20 Wall. 590, 620. The words of that section material here are those authorizing this court to reëxamine the judgments of the state courts "where any title, right, privi

of

any statute

the United States, and the decision is against the title, right, privilege, or immunity specially set up or claimed under such statute." There can be no doubt that the claim made here was specifically set up, claimed, and denied in the state courts. The question, therefore, precisely stated, is whether it was a claim of a right or immunity under a statute of the United States. Recent decisions of this court remove all doubt from the answer to this question. McCormick v. Market Bank, 165 U. S. 538; California Bank v. Kennedy, 167 U. S. 362; San José Land and Water Co. v. San José Ranch Co., 189 U. S. 177; Nutt v. Knut, 200 U. S. 12; Rector v. City Deposit Bank, 200 U. S. 405; Illinois Central Railroad v. McKendree, 203 U. S. 514; Eau Claire National Bank v. Jackman, 204 U. S. 522; Hammond v. Whittredge, 204 U. S. 538. The principles to be derived from the cases are these: Where a party to litigation in a state court insists, by way of objection to or requests for instructions, upon a construction of a statute of the United States which will lead, or, on possible findings of fact from the evidence may lead, to a judgment in his favor, and his claim in this respect, being duly set up, is denied by the highest court of the State, then the question thus raised may be reviewed in this court. The plain reason is that in all such cases he has claimed in the state court a right or immunity under a law of the United States and it has been denied to him. Jurisdiction so clearly warranted by the Constitution and so explicitly conferred by the act of Congress needs no justification. But it may not be out of place to say that in no other manner can a uniform construction of the statute laws of the United States be secured, so that they shall have the same meaning and effect in all the States of the Union.

It is clear that these principles govern the case at bar. The defendant, now plaintiff in error, objected to an erroneous construction of the Safety Appliance Act, which warranted on the evidence a judgment against it, and insisted upon a cor