assistant, the _libripens_, presented himself with a pair of scales. The slave with certain fixed formalities was handed over to the vendee--the copper was weighed by the _libripens_ and passed to the vendor. So long as the business lasted it was a _nexum_, and the parties were _nexi_; but the moment it was completed, the _nexum_ ended, and the vendor and purchaser ceased to bear the name derived from their momentary relation. But now, let us move a step onward in commercial history. Suppose the slave transferred, but the money not paid. In _that_ case, the _nexum_ is finished, so far as the seller is concerned, and when he has once handed over his property, he is no longer _nexus_; but, in regard to the purchaser, the _nexum_ continues. The transaction, as to his part of it, is incomplete, and he is still considered to be _nexus_. It follows, therefore, that the same term described the Conveyance by which the right of property was transmitted, and the personal obligation of the debtor for the unpaid purchase-money. We may still go forward, and picture to ourselves a proceeding wholly formal, in which _nothing_ is handed over and _nothing_ paid; we are brought at once to a transaction indicative of much higher commercial activity, an _executory Contract of Sale_. If it be true that, both in the popular and in the professional view, a _Contract_ was long regarded as an _incomplete Conveyance_, the truth has importance for many reasons. The speculations of the last century concerning mankind in a state of nature, are not unfairly summed up in the doctrine that "in the primitive society property was nothing, and obligation everything;" and it will now be seen that, if the proposition were reversed, it would be nearer the reality. On the other hand, considered historically, the primitive association of Conveyances and Contracts explains something which often strikes the scholar and jurist as singularly enigmatical, I mean the extraordinary and uniform severity of very ancient systems of law to _debtors_, and the extravagant powers which they lodge with _creditors_. When once we understand that the _nexum_ was artificially prolonged to give time to the debtor, we can better comprehend his position in the eye of the public and of the law. His indebtedness was doubtless regarded as an anomaly, and suspense of payment in general as an artifice and a distortion of strict rule. The person who had duly consummated his part in the transaction must, on the contrary, have stood in peculiar favour; and nothing would seem more natural than to arm him with stringent facilities for enforcing the completion of a proceeding which, of strict right, ought never to have been extended or deferred.