2. In every case where one man has a right to exclude another from his land, the law encircles it, if not already enclosed, with an imaginary fence; and entitles him to a compensation in damages for the injury he sustains by the act of another passing through his boundary, denominating the injurious act a breach of the enclosure. Hamm. N. P. 151; Doct. & Stud. dial. 1, c. 8, p. 30; 2 Whart. 430.