It seems obvious, on the one hand, that any conception of arbitration as a means of "settling" industrial disputes involves the necessity of some such provision as s. 48, and, on the other hand, that any such provision is likely to live in the shadow of difficult constitutional questions. It was only by the narrowest of margins that what is now s. 48 (2) escaped being held unconstitutional in the Waterside Workers' Case [1] . The ground of attack was that the Parliament, in enacting that an award should continue in force after the period specified in it, was assuming directly to prescribe industrial conditions and therefore transcending the limits of the power given by s. 51 (xxxv.) of the Constitution. It is unnecessary to consider the questions raised in the Waterside Workers' Case [1] or the further somewhat intricate questions discussed in Federated Gas Employees' Industrial Union v. Metropolitan Gas Co. Ltd. (Gas Employees' Case) [2] , R. v. The Commonwealth Court of Conciliation and Arbitration; Ex parte Victorian Railways Commissioners (Australian Railways Union's Case) [3] and Australian Tramway and Motor Omnibus Employees' Association v. Commissioner for Road Transport and Tramways (N.S.W.) (Tramway Employees' Case) [4] . Nor is it necessary to discuss the purpose or effect of sub-s. (4) of s. 48, which first appeared in 1947, taking the place of the old s. 28 (3), which was considered in the two last-mentioned cases. For present purposes it is necessary only to point out that the present s. 48, like the old s. 28, contemplates an award made in settlement of a dispute and having operation, as an award representing the will of the Court or commissioner, only during a period which must be specified in it and which must not exceed five years. What follows is designed to cover any gap between the expiration of the specified period and the making of a new award, and is incidental and subsidiary. The position was thus explained by Dixon J. in the Australian Railways Union's Case [5] : "The award is kept alive under sec. 28 (2)", - now s. 48 (2) - "not by force of an arbitral decision, but by direct legislative enactment which operates notwithstanding that by arbitral decision a period of duration has been fixed for the award and that that period has expired. The authority to do this has been considered" - i.e., in the Waterside Workers' Case [1] - "to belong to the Legislature because to hold an existing industrial regulation in force during the interval between arbitral decisions made in the settlement of disputes appeared to be fairly incidental to the subject matter of sec. 51 (xxxv.). To empower the Court of Conciliation and Arbitration to make alterations in the terms of the award so kept alive seems a further incident of the power, because, if it is right to retain in force by direct enactment an expired award, it is a reasonable consequence that, in case of unfairness or hardship, the Court should be allowed to exclude or modify the operation of the terms or conditions found inappropriate. But it must be remembered that all this is a result of the expiration of the industrial settlement effected by arbitration. It is the consequence of the fulfilment of the arbitral regulation which the Court making the award must be taken to have intended ". (The italics are mine.) The reference to the power of the Court "to make alterations in the terms of the award so kept alive" is a reference to the old s. 28 (3), which, as has been said, has been replaced by s. 48 (4). Section 48 (4) is probably in some respects wider and in some respects narrower than s. 28 (3) but in any case what Dixon J. said is just as applicable to s. 48 as to s. 28.