The plea in bar is insufficient. The facts stated in it arose inter alios. None are estopped by deed or by pleadings, but parties and privies; and none others can take advantage of an estoppel. The defendants are strangers to the record in the former suit. If the plaintiffs have heretofore made a mistake in calling upon a town not liable, this furnishes no reason why they should not be permitted to call on another town, whom they ha\e since discovered to be legally answerable.