Laches in seeking to enforce a right will, in many cases in equity, prejudice such right, for equity does not encourage stale claims nor give relief to those who sleep upon their rights; 4 Wait, Act. & Def. 472; Lane & B. Co. v. Locke, 150 U. S. 193, 14 Sup. Ct. 78, 37 L. Ed. 1049; In re Whitte more, 157 Mass. 46, 35 N. E. 93; this doc trine is based upon the grounds of public policy which requires for the peace of 'so ciety, the discouragement of stale claims ; Mackall v. Casilear, 137 U. S. 556, 11 Sup. Ct. 178, 34 L. Ed. 776. The question whether one is precluded from equitable relief by the staleness of his demand is for the court and not for the jury ; Raymond v. Flavel, 27 Or. 219, 40 Pac. 158.
It has been held to be inexcusable for thirty-six years ; Fuller v. Montague, 59 Fed. 212, 8 C. C. A. 100, 16 U. S. App. 391; twenty seven years, unexplained; Felix v. Patrick, 145 U. S. 317, 12 Sup, Ct. 862, 36 L. Ed. 719; twenty-three years ; Ware v. Galveston City Co., 146 U. S. 102, 13 Sup. Ct. 33, 36 L. Ed. 904; 22 years during which the defendant company spent much, labor and money in improvements; Gildersleeve _1, Min. Co., 161 U. S. 573, 16 Sup. Ct. 663, 40 L. Ed. 812 ; twenty-two years after knowledge of the facts ; Halstead v. Grinnan, 152 U. S. 412, 14 Sup. Ct. 641, 38 L. Ed. 495 ; nineteen years, on a bill to establish a trust; Hinchman v. Kelley, 54 Fed. 63, 4 C. C. 7 U. S. App. 481; fourteen years, in the assertion of title to lands which meantime had been sold to settlers ; St. Paul, S. & T. F. Ry. Co. v. Sage, 49 Fed. 315, 1 C. C. A. 256, 4 U. S. App. 160 ; ten years, in proceedings to enforce a trust in lands ; Abraham v. Ordway, 158 U. S. 416, 15 Sup. Ct. 894, 39 L. Ed. 1036; ten years, after the foreclosure and sale' of a railroad in a bill by a stockholder to set aside the sale for collusion and fraud which were patent on the face of the proceedings ; Fos ter v. R. Co., 146 U. S. 88, 13 Sup. Ct. 28, 36 L. Ed. 899 ; nine years in a suit to have a deed declared a mortgage on the ground that it was obtained by talaing advantage of the grantor's destitute condition ; De Martin v. Phelan, 51 Fed. 865, 2 C. C. A. 523, 7 U. S. App. 233 ; nine years to annul a foreclosure where the plaintiff was an ignorant negro whose confidence was abused; McIntire v. Pryor, 173 U. S. 38, 19' Sup. Ct. 352, 43 L. Ed.
606; eight years' acquiescence in a trade mark for metallic paint, which the defendant had built up an extended market for his product ; Princes' Metallic Paint Co. v. Mfg. Co., 57 Fed. 938, 6 C. C. A. 647, 17 U. S. App. 145; eight years in proceedings where complainant in consideration of 810, 000 had released certain claims and sought to set the release aside on the ground that it was entitled to a much larger sum than it received ; Thorn Wire Hedge Co. v. Mfg. Co., 159 U. S. 423, 16 Sup. Ct. 94, 40 L. Ed. 205 ; three years, where a person bought property of uncertain value and after three years brought suit to rescind the contract on the ground of fraudulent representation ; Saga dahoc Land Co. v. Ewing, 65 Fed. 702, 13 C. C. A. 83, 31 U. S. App. 102. Twelve years' unexplained delay in suing for the infringe ment of a patent precludes the recovery of profits or damages ; Safety Car Heating & Lighting Co. v. Car Heating Co., 174 Fed. 658, 98 C. C. A. 412; five years' delay, after discovery of a fraud, to file a bill to set aside a divorce decree for such fraud, is a bar; Horton v. Stegmyer, 175 Fed. 756, 99 'C. C. A. 332, 20 Ann. Cas. 1134.
To, constitute laches to bar, a suit there must be knowledge, actual or imputable, of the facts which should have prompted ac tion or, if there were ignorance, it must be without just excuse; Hausman v. Kelley, 38 Minn. 197, 36 N. W. 333, 8 Am. St. Rep. 661; see Hilliard v. Wood Carving Co., 173 Pa. 1, 34 Atl. 231; Johnston v. Min. Co., 148 U. S. 360, 13 Sup. Ct. 585, 37 L. Ed. 480; but where there is ignorance of the party's right, laches may be excused ; 2 Ball & B. 104; Gross v. Mfg. Co., 48 Fed. 35 ; Foster v. R. Co., 146 U. S. 88, 13 Sup. Ct. 28, 36 L. Ed. 899; Dice v. Brown, 98 Ia. 297, 67 N. W. 253. Evidence that complainant had ar ranged to dispose of land bequeathed to her, is evidence that she' knew of the existence of a will, and a delay of twenty years in bring-' ing an action to set aside its probate is laches; Corby v. Trombley, 110 Mich. 292, 68 N. W. 139. Defence of laches, on the ground that plaintiff might by inquiry have learned the facts relied on, is not available to de fendant, who was under obligation to dis close such facts without inquiry, defendant having suffered no harm ; Krohn v. William son, 62 Fed. 869.