If A has, at B's request, incurred a liability by reason of which A is subsequently bound to pay a debt to C upon which B was primarily liable, A may recover from B for such payment although B did not expressly request A to make such payment. Thus, if A has become surety for B, at B's request, and A is obliged to pay the debt, A may recover such payment from B.1 This right of recovery does not, however, rest on express contract of any sort between the parties. One surety who has paid more than his proportionate share of the debt may recover from his co-sureties.2 If A is bound by law to pay a debt for which B is primarily liable, such payment is not voluntary, and A can recover. Thus, where certain damages for opening streets must by law be paid out of a county treasury, although the liability therefor is against the city in the first instance, such payments are not voluntary, and the county may recover therefor from the city.3 So if a county agrees to pay for certain fire plugs which by order of the fiscal court are to be entered on the contract of the water-works company with the city, and the city is thus obliged to pay for them, it may recover from the county.4 If B has executed and delivered a negotiable instrument to A, in whose hands it is unenforceable, and A sells such negotiable instrument to X, a bona fide holder, who enforces the instrument against B, B may recover from A. Thus where a city issues bonds to a corporation, in payment of an ultra vires subscription by the city to the capital stock of such corporation, and the corporation delivers the bonds to a bona fide purchaser in whose plying a promise to pay, recovery could be had.) bauds they are enforceable against the city, the city may maintain an action against the corporation for the proceeds of such bonds.5 A entered into a contract with B for the sale of real property, by the terms of which contract A reserved as his own a building thereon. Subsequently, at B's request, A made to X a warranty deed for such property with full covenants of warranty, X having purchased B's rights in such contract. X claimed the building by force of the deed, and B was obliged to pay X the value of such improvements for the privilege of removing them. It was held that A could recover from B the amount thus paid, since B got the benefit thereof in the additional price received by him on sale of his interests in such property.6

1Hall v. Smith, 5 How. (U. S.) 96; Curtig v. Parks, 55 Cal. 106; Chamberlain v. Lesley, 39 Fla. 452; 22 So. 736; Kennedy v. Gaddie (Ky.), 32 S. W. 408; Gibbs v. Bryant, 1 Pick. (Mass.) 118; Merchants' National Bank v. Opera House Co., 23 Mont. 33; 75 Am. St.

Rep. 499; 45 L. R. A. 285; 57 Pac. 445.

2 Berlin v. New Britain School Society, 9 Conn. 175; Rushworth v. Moore, 36 N. H. 188; Aldrich v. Aldrich, 56 Vt. 324; 48 Am. Rep. 791.

3 Lancaster County v. Lancaster, 160 Pa. St. 411; 28 Atl. 854.

4 Stanford (City of) v. Lincoln County (Ky.), 61 S. W. 463.