A. N. Varma, J. - This is a defendant's appeal arising out of a suit for recovery of Rs. 21,330/- together with pendente lite and future interest at the rate of six per cent per annum : The court below having decreed the suit for those reliefs, the defendant has filed this first appeal.

Shortly, the plaint case was that the plaintiff firm was given a contract by the Local Self Government Engineering Department, Saharanpur for laying down sewer lines at Dehradun. The contract was signed by the parties thereto on 16-8-1980. In the course of the execution of the work which started on 16-9-1960 and completed on 31-12-1962, the concerned officers of the Department discovered that the proposed depth of the sewer lines in the drawings and maps given to plaintiff for execution of the work were shallow, Realising this mistake the Department gave to the plaintiff revised drawings and specifications according to which the plaintiff was required to dig much deeper than originally shown in the plan. The plaintiff protested against this on the ground that this would involve considerable extra work. At first the Department insisted that the plaintiff should carry out the work in accordan