Opinion by

The Act of April 26, 1883, P. L. 14, authorizes the appointment of policemen by the managers of any agricultural society, “whose duty it shall be to preserve order within and around the grounds of said society.” Among the powers given to such policemen is that of ejecting from the grounds of the society all persons “who shall be guilty of. disorderly conduct, or who shall neglect or refuse to pay the fee or observe the rules prescribed by said society,” together with the legal authority of a constable in making arrests.

The defendant in this case was a policeman appointed under the act referred to. The assault and battery for which he is indicted was the arrest of the prosecutor, and his ejection from the grounds of the society. His defense is that the prosecutor was guilty of disorderly conduct, in recklessly driving his hack among persons on foot, endangering their safety.

The trial judge instructed the jury that, to justify the defendant’s action in the premises, “ it is incumbent upon him to show that this prosecutor was disobeying some of the rules and regulations of the agricultural society that had been enacted by the authority of that society.” There being no evidence of such disobedience, or of the existence of such rules or regulations, the jury were instructed that there was no justification, and that if they believed the defendant had committed the assault as charged they should find him guilty.

In this instruction there was error. Disobedience of a rule of the society is not the only offense under the statute for which the offender may be arrested or ejected from the grounds of the society. Disorderly conduct is expressly made a cause, and it was not necessary for the society to enact a rule forbidding disorderly conduct in order to prevent it, or arrest for its- commission. The statute gives the policemen the power of a constable *463iu making arrests, and at common law a constable may, upon view, arrest for disorderly conduct amounting to a breach of the peace. Driving in such a manner as to endanger other persons is unquestionably a breach of the peace. It was for the jury to determine,- first, whether the prosecutor was guilty of a breach of the peace, or of disorderly conduct; and, next, whether the defendant, in the exercise of his authority, employed an unnecessary degree of force, to the injury of the prosecutor. If the conduct of the prosecutor was such as to make him legally liable to arrest or ejection from the grounds of the society, the defendant had a legal right to arrest or eject him, and in so doing to use all the force reasonably necessary for that purpose. On the other hand, if the defendant had not this right, or, if possessing it, he exercised it with unnecessary or unreasonable violence, he would be guilty of an assault and battery. The determination of these questions was the province of the jury alone.

Judgment reversed and a venire facias de novo awarded.