This case was tried without a jury, and there is no reason to doubt that, upon the facts found by the judge, it was correctly ruled that the plaintiffs could not recover in tort for the conversion of the property in dispute.
It is not enough to give the plaintiffs a right to recover, that they supposed they were selling bricks to the defendant, through Leonard his agent, and that they would not have sold them to Leonard on his sole credit. The judge found that they were in fact sold to Leonard. There was no fraud, no false representation of agency, or pretence on the part of Leonard that he was buying for any one else. He was a commission merchant, who was in the habit of purchasing goods on his own account, and who honestly bought the bricks for himself, and sold them to the defendant as his own. It was not a case of mistaken identity. The plaintiffs knew that they were dealing with Leonard; they did not mistake him for the defendant; nothing was said as to any other party to the sale. The conclusion is unavoidable that the contract was with him. The difficulty is, that the plaintiffs, if they had any other intention, neglected then to disclose it. It was a mistake on one side, of which the other had no knowledge or suspicion, and which consisted solely in the unauthorized assumption that Leonard was acting as agent for a third person, and not for himself.
It is elementary in the law governing contracts of sale and all other contracts, that the agreement is to be ascertained exclusively from the conduct of the parties and the language used when it is made, as applied to the subject matter and to known usages. The assent must be mutual, and the union of minds is ascertained by some medium of communication. A proposal is made by one party and is acceded to by the other in some kind of language mutually intelligible, and this is mutual assent. Mot. Con. 14. A party cannot escape the natural and reasonable interpretation which must be put on what he says and doe's, by showing that his words were used and his acts done with a *386different and undisclosed intention. Foster v. Ropes, 111 Mass. 10, 16. Daley v. Carney, 117 Mass. 288. Wright v. Willis, 2 Allen, 191. 2 Chit. Con. (11th Am. ed.) 1022. It is not the secret purpose, but the expressed intention, which must govern, in the absence of fraud and mutual mistake. A party is estopped to deny that the intention communicated to the other side was not his real intention. To hold otherwise would be to put it in the power of the vendor in every case to defeat the title of the vendee, and of those holding under him, by proving that he intended to sell to another person, and so there was no mutual assent to the contract.
In Boston Ice Co. v. Potter, 123 Mass. 28, cited by the plaintiffs, there was no privity of contract established between the plaintiff and the defendant. There was no evidence afforded in the conduct and dealings of the parties, that the defendant assented to any contract whatever with the plaintiff. A stranger attempted to perform the contract: of another party with the defendant.
In Hardman v. Booth, 1 H. & C. 803, there was abundant evidence that the contract was with another party, to whom the goods were sent, and not with the person who obtained possession of them and sold them to the defendant. In Mitchell v. Lapage, Holt N. P. 253, the goods were expressly bought of a firm, which, without the knowledge of the broker, had been dissolved by the withdrawal of two of its members.
We are referred to no case which supports the claim here made by the plaintiffs. Judgment for the defendant.