(after stating the facts as above). A bridge spanning a navigable river is an obstruction to navigation tolerated because of necessity and convenience to commerce upon land. Such a structure must be so maintained and operated that navigation may not be impeded more than is absolutely necessary, the right of navigation being paramount. It is incumbent upon the owner that the bridge be so constructed that it may be readily opened to admit the passage of craft, and maintained in suitable condition thereto. It is also his duty to place in charge those who are competent to operate the bridge, to watch for signals, and to open the bridge for the passage of vessels, and for the performance of 'such delegated duty he is responsible. It is also his duty to equip the bridge with proper lights giving warning of the position of the bridge and of its opening and closing. If for any reason the bridge cannot be opened, proper signals should be given to that effect, such as will warn the approaching vessel in time to heave to. A vessel, having given proper signal to open the bridge and prudently proceeding under slow speed, has, in the absence of proper warning, the right to assume that the bridge will be timely opened for passage. She is not bound to heave to until the bridge has been swung or raised and locked, and to critically examine the situation before proceeding (City of Chicago v. Mullen, 54 C. C. A. 94, 116 Fed. 292), but may carefully proceed at slow speed upon the assumption that the bridge will open in response to the signal, and may so proceed until such time as it appears by proper warning, or in reasonable view of the situation, that the bridge will not be opened (Manistee Lumber Company v. City of Chicago [D. C.] 44 Fed. 87; Central Railroad Company of New Jersey v. Pennsylvania Railroad Company, 8 C. C. A. 86, 59 Fed. 192), when it becomes the duty of the vessel, if possible, to stop, and, if necessary, to go astern.
We do not think that the ordinance of the city controls the situation. We do not doubt the power of the city to regulate the local usages of navigation, or that every vessel is bound to take notice of them and conform to them so far as they are reasonable and do not conflict with any law of Congress regulating commerce or with the general admiralty jurisdiction conferred upon the courts of the United States. The Brig James Gray v. The Ship John Fraser, 21 How. 184, 16 L. Ed. 106; Escanaba Company v. Chicago, 107 U. S. 678, 2 Sup. Ct. 185, 27 L. Ed. 442; Gulf, Colorado & Santa Fé Railroad Company v. Hefley, 158 U. S. 98, 104, 15 Sup. Ct. 802, 39 L. Ed. 910; Hennington v. Georgia, 163 U. S. 299, 311, 16 Sup. Ct. 1086, 41 L. Ed. 166; City of Chicago v. Mullen, supra. It is apparent that this ordinance was enacted for the protection of city bridges, and has reference only to the bridges owned by the municipality, the duty of maintaining lights being imposed upon the commissioner of public works. We need not consider whether the provision of the ordinance that vessels shall approach no nearer than the bridge protection while the danger signal is up, or while the bridge may be opening and closing, is reasonable. This ordinance can have no reference to the bridge in question, for it *274had no bridge protection; the ordinance manifestly applying to the bridges then owned and in use by the city and not to private bridges. The ordinance does not, if the city had the right so to order, determine what shall be prudent navigation. It did have the right to impose such reasonable condition as would prevent injury to its bridges. The question is, therefore, so far as the respondent is concerned, whether it was negligent in any duty owing to the vessel, and, so far as the vessel is concerned, whether she observed the proper rules of navigation, and whether she was negligent in placing herself in such position that collision with the unopened bridge would necessarily result.
With respect to the bridge, the signals maintained were appropriate signals to indicate the location of the bridge, and possibly the manner in which the signals were designed to be operated was proper and sufficient, under ordinary circumstances, to indicate an open or closed bridge. On the occasion in question the bridge could not be opened; but we are left in the dark with respect to the cause. The answer informs us that the bridge could not be opened, but gives no reason, nor does it inform the court why the respondent was not able to perform the duty which it owed to the on-coming vessel. It was incumbent upon the appellee by his answer to set forth specifically for the information of the court the facts which'prevented compliance with duty and which would excuse nonperformance, by alleging exculpatory facts, if any, showing that inability to perform a known duty arose from no neglect of its own. This has not been done either by its answer or by the evidence of its towermen in charge. We are simply informed that the towerman was unable to open the bridge, and the counsel for the respondent below objected successfully to any statement by the towerman—called by the libelant—of the reason that he could not open it or of the difficulty with the bridge, and the towerman contents himself with saying that he could not open the bridge himself; leaving the implication either of inability in himself or of some defect which the respondent did not wish disclosed. . The facts touching the bridge were peculiarly within the knowledge of the respondent and its agents, and it was its duty to fully explain the situation and to absolve itself of blame, and that burden cannot be cast upon the libelant. Failing to raise the bridge promptly when it had ample notice of the approach of the vessel, the respondent must be held guilty of neglect of duty. Failing to show that the delay was unavoidable, the presumption of negligence attaches, which it was its duty to overcome. And again, when the bridge tender found that the bridge would not open—and that was when the vessel was 150 feet north of Jackson street bridge and at least 300 feet away—in view of the situation we think it was the duty of the respondent to provide, and of the bridge tenders to give, some sort of warning signal that would timely notify the vessel of the difficulty and of the danger that was imminent, of which she could not otherwise be informed. We cannot hold the respondent absolved of fault.
Was the vessel in fault? She was proceeding under slow speed, sufficient only to give steerageway. She was approaching a bridge operated by electricity, and one that was raised quickly. She gave *275the proper signal when 150 feet north of the Jackson street bridge and at least 300 feet away. Upon entering the draw of that bridge the master discovered that the Metropolitan bridge was not opening. He at once ordered the engine stopped and then reversed 'at full speed. The vessel could not stop, even at that slow speed, in less than its length of 254 feet. The master did all that he could under the circumstances to avoid a collision brought about through failure of the respondent to perform its duty.
We think the court erred in its decree. It will therefore be reversed, and the cause remanded, with a direction to the District Court to pronounce for the libelant for the damages sustained by the vessel.