Cases in which one who has in his hands the property of another converts that property into some other form or mixes property of another with his own have been familiar both to courts of law and to courts of equity. Courts of law were concerned with legal ownership, and courts of equity with equitable ownership, but, up to a point, as is well known, the doctrines of the two systems were identical.
The passage I have cited from Frith v Cartland was cited with approval by Jessel MR in In re Hallett's Estate [16] . In that case [17] Jessel MR, citing earlier authority [18] , pointed out that the changing of property belonging to a person from one form into another makes no difference to the right of that person " "as long as it can be ascertained to be [the product of that person's property], and the right only ceases when the means of ascertainment fail" ". In that event, he said, the rule of Equity "gave you a charge - that if you lent £1,000 of your own and £1,000 trust money on a bond for £2,000, or on a mortgage for £2,000, or on a promissory note for £2,000, Equity could follow it, and create a charge". Dixon CJ and Fullagar J in Brady v Stapleton [19] said that:
it would be a great mistake to suppose that the great case of In re Hallett's Estate lays down a doctrine peculiar to money. On the contrary, it extends to money paid into a bank account, and so losing its identity as money, a doctrine which equity would never have had the slightest hesitation in applying to money physically existing or to any other kind of personal property to which it could, as a matter of practical possibility, be applied In In re Hallett's Estate [20] , the Master of the Rolls says: "Supposing the trust money was 1,000 sovereigns, and the trustee put them into a bag, and by mistake, or accident, or otherwise, dropped a sovereign of his own into the bag. Could anybody suppose that a Judge in Equity would find any difficulty in saying that the cestui que trust has a right to take 1,000 sovereigns out of that bag?" (Emphasis added.)
It follows that when an account holder makes a withdrawal for his own private purposes from an account containing a mixed fund, the rules of equity and the common law run parallel in attributing the withdrawal to the moneys that can lawfully be so used so far as those moneys extend.
1. (1952) 88 CLR 322 at 336-337.
2. (1880) 13 Ch D 696 at 719-720. See also Brady v Stapleton (1952) 88 CLR 322 at 337, per Dixon CJ and Fullagar J.
3. In re Hallett's Estate (1880) 13 Ch D 696 at 717.
4. Taylor v Plumer (1815) 3 M & S 562 at 575 [105 ER 721 at 726].
5. (1952) 88 CLR 322 at 337-338.
6. (1880) 13 Ch D 696 at 711.