1. The sole question in this appeal is whether the defendants are entitled to claim a set-off under 0 VIII, Rule 6 of the Code of Civil Procedure. The Courts below have declined to go into the merits of the set-off claimed on the ground that the sum claimed is not an ascertained sum and, therefore, does not fall within the provisions of the rule. In the Courts below the question of equitable set-off was also discussed, but in this Court the argument has been confined to the legal set-off provided by Rule 6. The suit was one for the balance of the price of castor seed sold by the plaintiff to the defendants. The defence, so far as we are now concerned with it, substantially was that this transaction formed one of the number of transactions between the parties in which there were payments to be credited on both sides and that on these other transactions on the date of suit a definite sum of Rs. 1126 was due to the defendants from the plaintiff. There were also certain minor ascertained sums as to one of which the claim of set-off has been allowed. If this were a claim for accounts in the sense that the defendants were asking the plaintiff to render an account and the sum due to the defendants could only be known to the latter when the accounts were rendered, there might be great force in the view taken by the Courts below. This, however, is not the nature of the claim. What the defendants say is that there were definite sums of debit and credit between the parties and that on the date of suit a definite known balance, the amount of which is given in the written statement, was due to the defendants from the plaintiff and that, this balance is shown in their account books as due on the date of suit. In any ordinary meaning of the term, the sum so claimed is an ascertained sum. The learned Counsel for the respondent has argued that a sum can only be treated as ascertained when it has been either admitted by the plaintiff or decreed by the Court. None of the authorities to which he has referred, supports this proposition, and the case of Edward Dalgleish v. Ramdin Singh Chowdhury 5 Ind. Cas. 67 : 14 C.W.N. 170 definitely contradicts it. The commentators on the Code are also all agreed that the words 'ascertained sum' are used to exclude such items as unliquidated damages and mesne profits the amount of which is not ascertainable until the Court determines them. Here the sum claimed is a definite ascertained amount, and we think that the Courts below were wrong in refusing to go into the defendants' claim. We accordingly set aside the decrees of both the Courts below and remand the case, through the lower Appellate Court to the Court of first instance with directions to enquire into the set-off claimed and to modify its decree accordingly if anything is found to be due to the defendants on account of set-off. The appellants will get their costs of this appeal including in this Court fees on the higher scale. Other costs will abide the result. It will not be open to the parties to re-agitate any question already decided except 'the questions which arise on the claim of set-off.