G.N.Prasad, J.

1. This is an appeal by the defendant. The plaintiff a registered firm carrying on business at Katrasgarh, in title district of Dhanbad, instituted the suit for recovery of a sum of Rs. 16,500 from the defendant, as per account given in Schedule A of the plaint.

2. The case of the plaintiff is that the defendant a coal merchant at Calcutta, had transanctions with the plaintiff since July 1950 for the purchase of coal through the plaintiffs agency. It was agreed that the price of all coal supplied by the plaintiff to the defendant would be paid to the plaintiff at Katras on presentation of bills and that in case of non-payment, the plaintiff would be entitled to charge interest at the rate of 12 per cent per annum. In pursuance of the above agreement, the plaintiff supplied coal to the defendant during the period 15th July 1950 to 26th June 1954 and also regularly submitted bills for all such despatches which were duly received by the defendant. The defendant used to make payments from time to time, either in cash or by cheque. The last payment was made by cheque on the 22nd January 1955. All supplies made to the defendant and all payments received from him we