construction. That which is open or manifest. 2. This word is usually applied to ambiguities which are said to be latent, or patent. 3. A patent ambiguity is one which is produced by the uncertainty, contradictoriness or deficiency of the language of an instrument, so that no discovery of facts or proof of declaration can restore the doubtful or smothered sense without adding ideas which the actual words will not of themselves sustain. . 4. A latent ambiguity may be explained by parol evidence, but the rule is, different with regard to a patent ambiguity, which cannot be explained by parol proof. The following instance has been proposed by the court as a patent ambiguity: If A B, by deed, give goods to one of the sons of J S, who has several sons, he shall not aver which was intended; for by judgment of law upon this deed, the gift is void for uncertainty, which cannot be supplied by averment. 8 Co. 155 a. And no difference exists between a deed and a will upon this subject. 2 Atk. 239. 5. This rule, which allows an explanation of latent ambiguities, and which forbids the use of parol evidence to explain a patent ambiguity, is difficult of application. It is attended, in some instances, with very minute nicety of discrimination, and becomes a little unsteady in its application. When a bequest is made to Jones, son of, Jones, or to Mrs. B, it is not easy to show that the ambiguity which this imperfect designation creates, is not ambiguity arising upon the face of the will, and as such, an ambiguity patent, yet parol evidence is admitted to ascertain the persons intended by those ambiguous terms. 6. The principle upon which parol testimony is admitted in these cases, is probably, in the first of them, a presumption of possible ignorance in the testator of the Christian name of the legatee; and in the second, a similar presumption of his being in the habit of calling the person by the name of Mrs. B. Presumptions, which being raised upon the face of the will, may be confirmed and explained by extrinsic evidence.