The opinion of the Court was delivered by

— The only question that could arise on the pleadings and evidence in this case was, whether the defendants had authority for what they did under the Acts of Assembly in relation to the powers of the city corporation and the ordinances enacted in pursuance of them. If they had authority to direct the run to be stopped for the purpose of pitching, grading and levelling the streets and regulating the ascents and descents of the streets and water-courses of the city, they were justified in what they did. Green v. The Borough of Reading, (9 Watts 382). The motives of the corporation in doing so cannot be examined into. Whether they were to promote the wishes of one man, or set of men, or to thwart others, or whether it was to benefit the corporation property or not, it is sufficient, if what they did was within the scope of their legal powers. It is evident, that inquiries into motives would lead into a wide field of surmise and conjecture: and as no motives are legally assignable to a law-maker beyond what are apparent on the face of his enactments, it would be as useless as it is hazardous. If one in the exercise of an authority deviates from the authority given by law, by doing more than is permitted, or doing it otherwise than he is directed, he may be amenable for such unauthorized acts, be his motives what they may; but as long as he acts within the sphere of his authority the motives or the cause of his doing so are in a legal point of view not examinable. This is the common principle in relation *517to a malicious prosecution, if the party had probable cause that fully justifies him, however malicious his motives may have been. So far is the principle carried, that if one has a legal and an illegal warrant, and arrests by virtue of the illegal warrant, yet he may justify by virtue of the legal one; for it is not what he declares, but the authority which is his justification. Doctor Greenville v. College of Physicians, (12 Mod. 387). If one distrains for an unjustifiable cause, yet when he comes to avow he need not insist on the cause for which he had distrained, but may justify for any lawful cause; the cause for which he distrained is not traversable. Fitz. Avowry 332; 3 Co. 26.

The court below, we think, erred in leaving it to the jury to say whether the object of the stoppage was with the view of improving the highway or to render the occupation of the Gas Works more convenient and valuable, even had there been any evidence on the subject, which does not appear. The only question was whether the defendants had authority to do the act complained of, and if they had they stood clearly justified. t

For the reasons above explained, the evidence offered by the plaintiff, which was excepted to, was inadmissible.

Judgment reversed, and a venire de novo awarded.