A purchase in the hope of an uncertain future profit; the purchase of a thing not yet inexistence or not yet in the possession of the seller, as, the cast of a net or a crop to begrown, and the price of which is to depend on the actual gain. On the other hand, if theprice is fixed and not subject to fluctuation, but is to be paid whether the gain begreater or less, it is called emptio spei. Mackeld. Rom. Law.