In the application of this Act to any colony, there shall, if the law of the colony so provides, be substituted for the amount of any fine specified in this Act, being a fine which may be imposed on summary conviction, such amount as may be provided by that law; and it shall be competent for the law of any colony to declare what amount of the local currency is to be treated for the purposes of this Act as equivalent to any amount of money specified in this Act.