the assignor who has instructed the latter to design a competing device which will avoid infringement. To anyone who with knowledge of the assignment cooperates with the assignor in the infringement. To a corporation organized after the assignment of which the assignor becomes the president; 10 or organized by the procurement of the assignor 11 or which has succeeded to the business and assets of a co-partnership which had agreed to cease infringement.12 But not to the manufacturer of an infringing machine upon the order of such a corporation except as to that particular machine. 13 The estoppel does not prevent the assignor or licensee from proving the state of the prior art so as to limit the scope of the patent; 14 nor from denying the infringement.15 It has been held that the assignor cannot escape the estoppel by alleging that he was induced by unfair representations to part with the patent; 16 but in a later case defendant was permitted to deny complainant's title to the patent and in a counter-claim allege equitable ownership in itself and pray for a decree quieting its title.17 A complainant is not estopped to attack a patent introduced by defendant as part of the prior art which was originally pleaded in the bill but afterwards abandoned.18 A plaintiff who has ratified a license by

8 Mergenthaler Linotype Co. V. Int. T. Mach. Co., 229 Fed. 168.

9 Schiebel Toy & Novelty Co. v. Clark, C. C. A., 217 Fed. 760; Dalton Add. Mach. Co. v. Moon-Hopkins Billing Mach. Co., 223 Fed. 51; Martin Gauge Co. v. Pollock, 251 Fed. 295, 298. But see RoessingErnst Co. v. Coal & Coke By-Product Co., C. C. A., 208 Fed. 990.

10 Roessing-Ernst & Co. v. Coal & Coke By-Products Co., C. C. A., 208 Fed. 990.

11 Martin Gauge Co. v. Pollock, 251 Fed. 295.

12 Dudlo Mfg. Co., v. Varley Duplex Magnet Co., C. C. A., 253 Fed. 745.

13 Roessing-Ernst Co. v. Coal & Coke By-Products Co., C. C. A., 208 Fed. 990.

14 Babcock & Wilcox Co. v. Toledo Boiler Works Co., C. C. A., 170 Fed. 81; Standard Plunger Elevator Co. v. Stokes, C. C. A., 212 Fed. 941; Schiebel Toy & Novelty Co. v. Clark, 217 Fed. 760; Mergenthaler Linotype Co. v. Int. Typesetting Co., 229 Fed. 168, 172; H. D. Smith & Co. v. Southington Mfg. Co., C. C. A., 247 Fed. 342.

15 H. D. Smith & Co. v. Southington Mfg. Co., C. C. A., 247 Fed.

342.

16 Vacuum Eng. Co. v. Dunn, C. C. A., 209 Fed. 219.

17 Cleveland Eng. Co. v. Galion D. M. Truck Co., 243 Fed. 405.

18 Mergenthaler Linotype Co. v. Int. Typesetting Co., 229 Fed. 168, 173.

collecting royalties and demanding accountings thereunder is estopped from repudiating the same upon the ground that it was executed without her authority.19

Where complainant for more than twelve years had not advertised its trade-mark, nor employed salesmen, nor made any attempt, to sell the goods so marked outside of a single State, the court held that it was estopped from suing for infringement a corporation which in ignorance of the plaintiff's rights had spent several thousand dollars in advertising in another State goods similarly marked.20

It was held that the successor to the rights of the lessee in a lease of a coal mine which had successfully resisted a suit by the lessor for a forfeiture of the lease and had operated the mine for two years, was estopped from asking a cancellation of the lease or a modification of its terms upon the ground that the lessor had misrepresented the quantity of coal.21 That a failure by the lessee in such a lease to discover coal seams beneath those which it had operated did not estop it from working such seams which were included in the general terms of the lease although they were subsequently discovered by successors of the lessor on adjacent property.22 Where a mortgage recognizes the priority of another mortgage previously executed, the mortgagee is estopped from denying the priority of such mortgages and bonds thereby secured.23

Creditors or others who have knowledge that their trustee or other representative is acting in collusion with the other side in a pending suit, are estopped if without excuse they remain silent. until after the decree.24 Beneficiaries of a trust who have avoided the charge of laches by the contention that the trust was not repudiated by the trustee in his lifetime, cannot, upon the accounting of the latter's executor, enforce charges for

19 Vose v. Roebuck Weather Strip & Wire Screen Co., 216 Fed. 523. 20 Theodore Rectanus Co. V. United Drug Co., C. C. A., 226 Fed. 548.

21 Browning v. Boswell, C. C. A., 215 Fed. 826.

22 Standard Pocahontas Coal Co.

v. New Pocahontas Coal Co., C. C. A., 252 Fed. 535.

23 Mississippi Valley Tr. Co. v. Washington Northern R. Co., 212 Fed. 376.

24 Re Dashiell, C. C. A., 246 Fed. 366.

which there would be no liability unless the trustee had converted the trust funds to his own use.25

Where executors had no authority to bind the estate by the contract upon which suit was brought, a stipulation that judg ment upon any verdict therein should be entered against them as executors did not bind them or the estate or estop them from denying the estate's liability.2

26

The doctrine of equitable estoppel does not effect the United States because land to which the Government asserts a title has been occupied and improved with the Government's knowledge.27 The payment by a municipal corporation of interest upon its bonds, warrants or other written obligations does not estop it from proving that they were issued fraudulently without consideration and ultra vires.28

In equity an estoppel in pais need not be pleaded since it is in effect a rule of evidence.29 At common law in the absence of a State statute upon the subject it is available as a defense under the general issue.30 If the State statute or practice requires an equitable estoppel to be pleaded, the Federal court sitting within the State must observe the rule in actions at law.31

§ 185b. Defense of election of remedies. The defense of the election of remedies is not a favorite of courts of equity.1 It has, however, been long observed and is well settled. Where two inconsistent remedies, proceeding upon irreconcilable claims of rights, are open to a suitor, the choice of one bars the other.3 A mistake in the assertion of an alleged right is not an election, because an election can consist only in a choice between two inconsistent remedies existing and not fancied. "Election is simply what its name imports; a choice shown by an overt act, between two inconsistent rights, either of which may be asserted

25 Alexander v. Fidelity Tr. Co., 238 Fed. 938.

26 Griggs v. Nadean, 221 Fed. 381. 27 Utah Power & Light Co. v. U. S., C. C. A., 230 Fed. 328.

28 Hornblower v. City of Pierre, C. C. A., 241 Fed. 450.

29 Shelton v. Southern Ry. Co., 255 Fed. 182.

30 Ibid.

31 Ibid.

$185b. 1 Friederichsen v. Renard, 247 U. S. 207, 211.

2 Ibid.

8 Ratchford v. Cayuga Co. Cold Storage & W. Co., 217 N. Y. 565.

4 Greenhall v. Carnegie Trust Co., 180 Fed. 812.

at the will of the chooser alone."5 That a party through mistake of law has attempted to exercise a right, to which he is not entitled, does not prevent his afterwards exercising another right, which he had and still would have unless barred by the previous attempt.6 Where the relief sought is substantially the same, although prayed upon different theories, there is no election by prosecuting either of them unsuccessfully.7

In case of a conditional sale an unsuccessful attempt to enforce a lien upon property or an action and judgment for the purchase price which has not been collected in full, does not prevent a recovery in specie. On the other hand, the recaption of the property is an election which prevents the recovery of the unpaid installments.10 The filing of a mechanic's lien is a concession, that the articles sold have ceased to be personal property and have become a part of the real estate, so that they cannot be replevied.11

It was held that the entry of judgment in a foreclosure suit, to which the tenant in possession is a defendant, is an election to terminate his lease which prevents the recovery of future rent when he upon the entry of judgment vacated the premises; although the mortgagee subsequently, against the tenant's opposition, obtained an order vacating the judgment and discontinuing the foreclosure suit.12 That the entry and part collection of a judgment for damages for breach of covenants, of which the sole consideration was certain promissory notes, is an election which prevents a defense to an action upon such notes for want or failure of consideration. 13 A suit to annul a contract

5 Mr. Justice Holmes in William W. Bierce Ld. v. Hutchins, 205 U. S. 340, 346.

6 Ibid.

7 So. Pac. Ry. Co. v. Bogert, 250 U. S. 483.

8 William W. Bierce, Ld. v. Hutchins, 205 U. S. 340.

9 Ratchford v. Cayuga Co. Cold Storage & W. Co., 217 N. Y. 565. But see Whitney v. Abbott, 191 Mass. 59, 63; Shipley Const. & Supply Co. v. Mager, 165 App. Div. (N. Y.) 866. Where after default the vendor elected to declare future pay

ments due and recovered judgment for them which was held to be an election.

10 Kelley-Springfield Road Roller Co. v. Schlimme, 220 Pa. 413; Minneapolis Harvester Works v. Hally, 27 Minn. 495; McBryan v. Universal Elevator Co., 130 Mich. 111.

11 Kirk v. Crystal, 118 App. Div. (N. Y.) 32; aff'd 193 N. Y. 622.

12 461 Eighth Ave. Co., Inc. v. Childs Co., 181 App. Div. (N. Y.) 742.

13 Karasik v. People's Trust Co., C. C. A., 252 Fed. 337. See also

for fraud, which has not been reduced to judgment, does not prevent an action for damages for the deceit.14 The cancellation. of a proof of claim upon a bankrupt's motion on the ground, that the claim was not provable because not dischargeable by the bankruptcy proceedings, prevents him from subsequently contending that the judgment was void.15 The exclusion in an action at common law upon a written contract of evidence, that the paper was not intended to be binding, when the ruling was upon the plaintiff's objection, estops him from maintaining in a subsequent suit in equity, to enjoin the former action, that the evidence was admissible at law only.16

The filing of a bill to set aside a transfer of assets by a corporation and for an account to the trustee of a stockholder who was alleged to be the owner of all the assets since he was in fact the corporation, is not an election, which prevents an amended bill praying that the assets and securities be returned to the corporation.17

§ 185c. Purchase for a valuable consideration. The defense of purchase without notice for a valuable consideration must be pleaded by the defendant or it is waived. An allegation in the bill that the defendants bought with knowledge of the fraud charge is surplusage and need not be proved.2 The defendant should state the date, parties and a summary of the contents of the deed of purchase. He should deny notice positively and should state the amount of the consideration. It is insufficient to plead that the defendant paid a "good and valuable consideration, to-wit, a certain sum of money. "'5 Notice to an individuai

J. L. Owens Co. v. Officer, C. C. A., 244 Fed. 47, 48, 53.

14 Friederichsen v. Renard, 247 U. S. 207; Bistline v. U. S., C. C. A., 229 Fed. 546.

15 Davis v. Wakelee, 156 U. S. 680, 685, 689, 691, 15 Sup. Ct. 555, 39 L. ed. 578.

16 Michaels v. Olmstead, 157 U. S. 198, 201, 15 Sup. Ct. 580, 39 L. ed. 671.

17 Greenhall v. Carnegie Trust Co., 180 Fed. 812.

§ 185c. 1 Boone V. Chiles, 10 Peters 177, 211, 212; Wright-Blodgett Co. v. U. S., 236 U. S. 397, 403; Wood v. Mann, Sumner 506.

2 U. S. v. Brannon, C. C. A., 217 Fed. 849.

3 Boone v. Chiles, 10 Peters 177, 211; Wright-Blodgett Co. v. U. S., 236 U. S. 397, 403.

4 Wood v. Mann, 1 Sumn. 506. 5 Secombe v. Campbell, 18 Blatchf. 108.