Manner in which duty may be levied. subject to such rules regulating the time, place and manner as the Financial Commissioner may prescribe, such duty shall be levied rateably, on the quantity of excisable article imported, exported, transported, collected or manufactured in, or issued from, a distillery, brewery or warehouse; Provided that duty may be levied (a) on intoxicating drugs by an acreage rate levied on the cultivation of the hemp plant, or by a rate charged on the quantity collected; (b) on spirit or beer manufactured in any distillery established, or any distillery or brewery licensed, under this Act in accordance with such scale of equivalents calculated on the quantity of materials used, or by the degree of attenuation of the wash or wort, as the case may be, as the state Government may prescribe; (c) on tari, by a tax on each tree from which the tari is drawn: Provided further that, where payment is made upon issue of an excisable article for sale from a warehouse established or licensed under section 22(a), it shall be made (a) if the state Government by notification so directs, at the rate of duty which was in force at the date of import of that article or (b) in the absence of such direction by the state Government, at the rate of duty which is in force on that article on the date when it is issued from a ware house.