Privilege for the benefit of trade, holds only betwixt landlord and tenant; not betwixt third persons and the owner of the soil]: as is exemplified by Morgan v. Arthurs, 3 Watts 140, and Lemar v. Miles, 4 Watts 330. In the first of these, a steam engine ' set up by the owner to drive a saw mill, was held to be a part of the freehold and subject to a mechanic’s lien; while in the second, an *107engine set up by a lessee, to drive a salt works, was seized and sold as personal by his creditors. Here the engine was erected by the owner of the mill, and it was consequently a part of the freehold. Judgment affirmed.