53 Pa. Stat. § 16623
If in any case the said marshal or other officer of police authorized as aforesaid, shall certify in writing to the major general or other commanding officer of the military division composed of said city and county, that there is an existing riot, tumult or unlawful assemblage within said police district or said county, which the said police force under his command is not in his opinion competent to suppress without further aid, and shall require the said major general or commanding officer to assist him with the military force under his command, and the said major general or commanding officer shall give the necessary orders to the effect, that such military force or such part thereof as he shall deem necessary, shall be mustered immediately into the service of the commonwealth, and be subject to the laws applicable to such service, and shall proceed to any part of said city or county to restore the public peace, by suppressing such riot, tumult or unlawful assemblage, and by seizing and securing the offenders therein for trial and punishment according to law; and it shall be lawful for said military force to proceed in suppression of such riot, tumult or unlawful assemblage, as aforesaid, by such military force, and in like manner as in case of war or public insurrection, and the said military force shall continue and remain in service, and upon duty under military command and subordination until the said marshal shall certify in writing to the said major general or commanding officer, that said riot, tumult or unlawful assemblage is entirely suppressed; and the military body so called into service, shall be entitled to be paid while on actual duty as follows, to wit: two dollars a day to the privates, non-commissioned officers and musicians, and four dollars a day to the commissioned officers, and two dollars a day for each horse employed, which sum shall include all expenses of subsistence; the amount thereof, together with the expense of their ammunition and artillery used on such duty, shall be paid out of the treasury of said county; but such military body shall not be required to march to the place of any such riot, tumult or unlawful assemblage, until after the said marshal or other person authorized by this act to make proclamation as aforesaid, in an audible voice, and as near to the rioters or persons unlawfully assembled as he can safely and with convenience go, shall have commanded such rioters or persons unlawfully assembled, and all other persons not being then and there on duty as police or a part of his posse, civil or military, to return to their lawful homes and business.
53 P.S. § 16623