afterward drew up the opinion of the Court' Two exceptions have been taken to the instructions of the court to the jury.
1. Because the jury were instructed, that the evidence reported, if believed, proved that the defendant’s cow was lawfully impounded, whereas the defendant’s counsel contend, that a field driver cannot lawfully impound any catt'te except in a town pound. This exception cannot be allowed, because it appears by the evidence, that the cow was found in one Wild’s mowing ground damage-feasant, and was impounded by his order, he claiming fifty cents for the damage done. This he was authorized to do by St. 1788, c. 65, § 3, with or without the aid of a field driver ; and although the cow was driven into the road by Wild, by the direction of the field driver, and was there delivered to him, yet it is not to be inferred*, that the cow was impounded for going at large ; and clearly the cow *417was not found going at large, and could not lawfully be impounded by the field driver for that cause. As, therefore, it does not appear, that the cow was impounded for going at large, but, on the contrary, it does appear that the field driver acted under the direction of Wild, and that the cow was found in Wild’s mowing field damage-feasant, we think that this exception is clearly unfounded.
2. And the other exception, as it appears to us, is equally unfounded. The jury were instructed, that if they were not satisfied, that the defendant was present when his cow was taken, or that the act was done by his direction, or procurement, or with his knowledge or consent at the time, yet if they were satisfied, from the evidence, that the defendant afterwards, while the men who took the cow were engaged in the act of driving her from the barn to his house, and with a knowledge of the facts, that she had been impounded and restrained, and had been delivered from the place where she' had been restrained, voluntarily joined and aided them in completing and accomplishing their object, the plaintiff was entitled to a verdict.
This direction, we think, was perfectly correct. The principle is well established, that if a person agree to a trespass which has been committed for his benefit, he thereby becomes a principal trespasser ab initio ; a fortiori, if he aids in completing the trespass. Such a subsequent approval is considered as equivalent to a previous command. 4 Inst. 317 ; Gibson’s case, Lane, 90 ; Com. Dig. Trespass, C 1; Brooke’s Abr. Trespass, pl. 113, 256 ; Bac. Abr. Trespass, G. The evidence clearly proves, that the cow was liberated for the benefit of the defendant, so that the cases cited are directly in point and fully sustain the instructions to the jury.
Judgment of the Court of Common Pleas affirmed.