This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
Another line of authorities, greater numerically, and treating the fiction of implied contract more rationally, allow the real owner to recover from the wrongdoer, even where the wrongdoer has not sold the property.1 Where this theory obtains it is, of course, immaterial whether the property has been bartered or sold on credit, since the liability on the common counts in assumpsit exists even if the property converted has not been sold at all. Under this theory assumpsit will lie where the wrongful act consists in making use of property, and not in attempting to deprive the owner of it permanently. Thus A was to work for B for a year, giving B his entire time. Instead A used B's team on A's business. It was held that B could recover a reasonable compensation for such use from A, on the theory of an implied promise, even if A in fact did not intend to pay therefor.2