The first and the most important question in the case relates to the property in the machine. It was a structure of great weight and could not be finished by the plaintiffs at their own building, but must have been in the same local situation before as after a delivery ; and when completed, no actual and perhaps no symbolical delivery would have been necessary. The parts were to be removed by Burbank to his works, but the possession for that purpose was not a delivery The plaintiffs’ workmen were to follow the machine to Burbank’s land, and there complete it, and they accordingly did so, and nearly finished it before the attachment. It was put in operation as an experiment, and operated to some extent, but important parts were wanting to make it work advantageously. The plaintiffs would not have been justified in offering it to Burbank as finished ; and if they had refused to complete it, Burbank could not have maintained trover for it, but his remedy would have been on his contract. On the whole, we are all satisfied that the evidence did not show a transfer of the property to Burbank.

The other question is, whether an action of trespass will lie for the plaintiffs. The objection on the part of the defendant is, that they had not such possession as will enable them to maintain the action. We have not deemed this point to be so clear as the main point. The machine was in the building of Burbank, which was in his possession. Accord*33ng to his agreement, however, the plaintiffs had a right to go there to finish the machine, and he could not maintain trespass quare clausum against them. We think that it was so far within the control and in the possession of the plaintiffs, under their contract and the permission of Burbank, that the action will lie. If a watchmaker puts up a clock in a house, under an agreement that if it shall keep good time the owner of the house will purchase it, we think that, until the trial is made, tlie watchmaker remains in possession so as to be able to maintain trespass.

Judgment for the plaintiffs.