The witness has by reference to copies of invoices existing on file No. C. 157 (Exh. 11) consisting of 391 pages containing the record relating to all the transactions of Orissa Industries Ltd. with the Cuttack Plumbing Stores and Nakula Sahu & Sons and ledgers [Exh. 12 to 12(4)] evidencing all transactions with Nakula Sahu, Cuttack Plumbing Stores and N. C. Sahu & Sons and containing cross references to invoices testified that it was for the first time in June 8, 1959 that the Cuttack Plumbing Stores purchased three wash hand basins 22" X 16" of Class I quality from his Company; that from June, 1961 to February, 1962, the Cuttack Plumbing Stores purchased 1704 Class II and 300 Class III wash hand basins 22"X16" from his concern; that apart from these sales there has been no other sale of wash hand basins to accused Nakula Sahu or Cuttack Plumbing Stores or N. C. Sahu & Sons; that Nakula Sahu was transacting business with his Company in respect of all the aforesaid invoices; that in the years 1961 and 1962, the price of class I wash hand basin 27 ' 'X16 was about Rs. 53/ per piece and price of Class II and Class III wash band basin 27 ' 'X16 ' ' was about Rs. 38.50 and Rs. 23/ per piece respectively; that glass and ceremic products became subject to Central Excise duty for the first time with effect from the mid night of February 28,1961 and that from that date marking of gradations by stamp and indelible ink were given on wash hand basins produced by his Company; that wash hand basins produced by his Company are marked with rubber stamp as 1st, or 2nd or Com.