FACTS :- The Khandesh Spinning and Weaving Mills Co., Ltd. (plaintiffs) were carrying on business as a Spinning and Weaving Mills at Jalgaon, and for the purpose of that business they used to import charcoal within the jurisdiction of the Jalgaon Borough Municipality (defendants). There were difficulties about obtaining charcoal, with the result that the plaintiffs resorted to the user of fuel oil or furnace oil for the purpose of heating their boiler. The defendants claimed that the fuel oil or the furnace oil which was thus imported by the plaintiffs within their jurisdiction fell under item 73 of class in of sch.A to these rules and by-laws framed by them and which provided for the levy of an octroi duty at the rate of annas -/4/- per maund on "all articles of sizing used in mill industries, oils used for machinery, boiler composition, spindle oil, china clay, grease, lubricating oils of all kinds". The defendants accordingly levied on the fuel oil or the furnace oil which was thus imported by the plaintiffs, from and after 21st May 1946, octroi duty at this rate of annas -/4/- per maund. Disputes thereupon arose between the plaintiffs and the defendants, and correspond