A law declared to be an emergency law shall contain a preamble setting forth the facts constituting the emergency, and shall contain the statement that such law is necessary for the immediate preservation of the public peace, health, safety or convenience. [A separate vote shall be taken on the preamble by call of the yeas and nays, which shall be recorded, and unless the preamble is adopted by two-thirds of the members of each house voting thereon, the law shall not be an emergency law; but] if the governor, at any time before the election at which it is to be submitted to the people on referendum, files with the secretary of the commonwealth a statement declaring that in his opinion the immediate preservation of the public peace, health, safety or convenience requires that such law should take effect forthwith and that it is an emergency law and setting forth the facts constituting the emergency, then such law, if not previously suspended as hereinafter provided, shall take effect without suspension, or if such law has been so suspended such suspension shall thereupon terminate and such law shall thereupon take effect: but no grant of any franchise or amendment thereof, or renewal or extension thereof for more than one year shall be declared to be an emergency law. [See Amendments, Art. [See Amendments, Art. LXVII.]