of the enrichment. This, however, is absurd, because one surety could then recover the whole debt from another, who could thereupon turn about and on the same principle recover it back. The learned author does not meet this difficulty; but he assumes without argument that the plaintiff can recover only a proportionate share. That measure of recovery can be ascertained, however, only upon the theory that there is already in existence a duty to contribute pro rata, and that the enrichment of the defendant is the advantage which he retains upon a refusal. If that duty is made to depend upon the theory of unjust enrichment, there is a complete circle of reasoning, as thus: the defendant is unjustly enriched by his proportionate share of the debt, because he ought to pay it and does not; but he ought to pay it, because if he does not he is un- justly enriched. It follows that, if the plaintiff is to recover at all, it must be upon some other principle than that of unjust enrichment.
One more case will suffice. In Phillips v. Homfray,[1] the facts, shorn of some complexity, were these. The plaintiff was the owner, of an underground road through a mine, which road, so far as he knew, was unused. It appeared, however, that the defendant had used it for a considerable period of time, and at a considerable saving of expense. When the plaintiff discovered the truth, he brought suit to recover an amount equal to the defendant's savings. There was no evidence that the road suffered any injury by the defendant's unauthorized use. The court denied the recovery; but the learned author regards the case as an illustration of the doctrine of unjust enrichment, and would permit a recovery. The court said in italicized words that the defendant "saved his estate expense, but he did not bring into it any additional property or value belonging to another," or, in other words, denied that the plaintiff suffered any expense. The learned author meets this argument by pointing out, what is perfectly true, that the defendant was enriched by the amount of his savings; but he fails to point out that the plaintiff was at any expense, and that is the very difficulty of the case that the court felt. The point is unanswerable. The plaintiff was not deprived of the use of the property himself, because he made no attempt to use it. He supposed all along that it was unused, and there was nothing to show that, if he had tried to use it, the defendant would have prevented him. He was not deprived of any rentals which a third party might
- ↑ 24 Ch. Div. 439.