3 Thus, although a bill of sale of a vessel, absolute in its terms, expresses a certain sum as the consideration, the vendor may prove an oral agreement to pay an additional sum upon a certain contingency, and recover such sum upon the happening of the event. Clark v. Deshon, 12 Cush. 589 (1853). An agreement in writing, by which a mortgagee agrees to deliver up the mortgage note to be cancelled, upon the doing of certain things by the mortgagor, "which settles all accounts with said mortgagor," may be shown by parol evidence to have been intended as a settlement of all claims for property taken from the premises by the mortgagor. Hemenway v. Bassett, 13 Gray, 378 (1859).

4 Wheeler v. Billings, 38 N. Y. 263 (1868) ; Miller v. Goodwin, 8 Gray, 542 (1857). Parol proof of the actual consideration of a sale is admissible, although a bill of sale is executed by the seller, and a bond by the purchaser, as part of the same transaction, if neither of them states the terms and conditions of the sale. Paget v. Cook, 1 Allen, 522 (1861).

5 Story on Agency, § 79, 80; Keating v. Price, 1 Johns. Cas. 22; Mills v. Wyman, 3 Pick. 207; 1 Greenl. on Evid. § 304; 1 Phil. & Am. on Evid. 757; Ballard v. Walker, 3 Johns. Cas. 60; Pothier on Oblig. pt. 3, ch. 6, art. 2, n. 636; Munroe v. Perkins, 9 Pick. 298; Lattimore v. Harsen, 14 Johns. 330; White v. Parkin, 12 East, 578; Hotham v. East Ind. Co., 1 T. R. 638; Blood v. Goodrich, 9 Wend. 68; Youqua v. Nixon, Peters, C. C. 221.

6 Rohan v. Hanson, 11 Cush. 44 (1853).

§ 828. There are two species of ambiguity, namely, that which is apparent on the face of the instrument, and which cannot be rendered certain by the evidence of collateral facts and surrounding circumstances, admissible under the rules of construction, and which is called ambiguitas patens ; 1 and that which, although apparently certain and without ambiguity, for any thing that appears upon the face of the deed or instrument, is rendered ambiguous by extrinsic and collateral matter, out of the deed, which is called ambiguitas latens. A patent ambiguity cannot be explained by parol evidence;2 or, in the words of Lord Bacon: "Ambiguitas patens is never holpen by averment; and the reason is, because the law will not couple and mingle matter of specialty, which is of the higher account, with matter of averment, which is of inferior account in law; for that were to make all deeds hollow and subject to averments, and so in effect that to pass without deed which the law appointeth shall not pass but by deed." Where the Ian-guage descriptive of property or persons is uncertain3 and obscure, it is a latent ambiguity, which can be explained by evidence.4 But where the intention of the party is ambiguously expressed, but the property of persons clearly described, it is a patent ambiguity, and parol evidence will not be allowed. "Therefore, if a man give land to I. D., and I. S., et hceredibus, and do not limit to whether of their heirs, it shall not be supplied by averment to whether of them the intention was the inheritance should be limited. But if it be ambiguitas latens, then otherwise it is ; as if I grant my manor of S. to J. F. and his heirs, here appeareth no ambiguity at all. But if the truth be, that I have the manors both of South S. and North S., this ambiguity is matter of fact; and, therefore, it shall be holpen by averment whether of them it was that the party intended should pass." 1

1 1 Greenl. on Evid. § 297, 300; 1 Phil. Evid. ch. 10.

2 Doe v. Westlake, 4 B. & Al. 57; Doe v. Hiscocks, 5 M. & W. 363; Cheyney's Case, 5 Co. 68; Strode v. Russel, 2 Vern. 624; Harris v. Bishop of Lincoln, 2 P. Wms. 136; Hitchin v. Groom, 5 C. B. 520; Blossburg & Corning Railroad Co. v. Tioga Railroad Co., 1 Keyes, 486 (1864). But where it is necessary to determine the date of a promissory note in suit, and the name of the month is so inartificially written that, upon inspection, the presiding judge cannot determine whether it should be read June or January, extraneous evidence is admissible to show the true date. Fenderson v. Owen, 54 Me. 372 (1867).

3 Thus, a testator devised property to "my nephew, Joseph Grant." His brother had a son named Joseph Grant, and his wife's brother had a son of the same name. There being a latent ambiguity, parol evidence was admitted to show which Joseph Grant was meant by the testator. Grant v. Grant, Law R. 5 C. P.-380, 727 (1870).

4 Thus, goods were sent by sea to be delivered "at the Essex Railroad Wharf." The Essex Railroad owned but one wharf, which was by the side of their road, above two drawbridges. Parol evidence was admitted to prove that a wharf called Phillips's Wharf, below the bridges, was used by the railroad to receive merchandise at, and was generally known as the Essex Railroad Wharf, and was the wharf intended by the parties. Sutton V. Bowker, 5 Gray, 416 (1855).

§ 829. In the case of a latent ambiguity the actions of the parties previous to and contemporaneous with the contract are admissible to explain it. As, where a bargain is made for wheat, generally, without stating the quality, parol evidence may be given that the previous usage of the parties was to furnish wheat of a particular quality.2 So, where a party agreed in writing to pay partly in cash and in part by an order, parol evidence is admissible to show that the order was to be for sash and blinds, and not money.3 So, also, a receipt for money may be explained by showing that something short of the terms was intended, even though it read in full of all demands ;4 it. being conclusive only as to the amount paid, and

1 Bacon's Law Tracts, p. 99, 100. See also Morris v. Edwards, 1 Ohio, 189; 2 Starkie on Evid. 546. Thus, a testator devised "all my estate in Shropshire, called Ashford Hall," and parol evidence was admitted to prove the extent of the lands constituting the estate. Ricketts v. Turquand, 1 H. L. C. 472(1848).