rigorous manner, a duty in kind:  which, however, had existed long before his time:  we allude to the annona, or supply of corn for use of the army and capital.  This was a grievous and arbitrary exaction:  rendered still more so “by the partial injustice of weights and measures, and the expence and labour of distant carriage.”  In a time of scarcity, Justinian ordered an extraordinary requisition of corn to be levied on Thrace, Bithynia, and Phrygia; for which the proprietors, (as Gibbon observes,) “after a wearisome journey, and a perilous navigation received so inadequate a compensation, that they would have chosen the alternative of delivering both the corn and price at the doors of their granaries.”

Having thus given a connected and general view of the Roman commerce, we shall next proceed to investigate the progress of geographical knowledge among them.  In our chronological arrangement of this progress, incidental and detached notices respecting their commerce will occur, which, though they could not well be introduced in the general view, yet will serve to render the picture of it more complete.

It is evident that the principal accessions to geographical knowledge among the Romans, at least till their ambition was satinted, or nearly so, by conquest, must have been derived from their military expeditions.  It is only towards the time of Augustus that we find men, whose sole object in visiting foreign countries was to become acquainted with their state, manners, &c.

Polybius is one of the earliest authors who give us a glimpse of the state of geographical knowledge among the Romans, about the middle of the second century before Christ, the period when he flourished. lie was the great friend of Scipio, whom he accompanied in his expedition against Carthage.  From his enquiries while in Africa, he informed himself of the geography of the northern parts of that quarter of the world; and he actually visited the coast as far as Mount Atlas, or Cape Nun, beyond which, however, he does not seem to have proceeded.  He wrote a Periplus, or account of his voyage, which is not in existence, but is referred to and quoted by Pliny.  He possessed also more accurate information of the western coasts of Europe than was had before; derived, it would appear, from the voyages of some Romans.  Yet, with all this knowledge of what we may deem distant parts, Polybius was ignorant of the real shape of Italy, which he describes as stretching from east to west; a mistake which seems to have originated with him, and was copied by Strabo.

Varro, who was Pompey’s lieutenant during the war against the pirates, and obtained a naval crown on that occasion, among the almost infinite variety of topics on which he wrote, was the author of a work on navigation; unfortunately, however, only the title of it is extant:  had it yet remained, it would have thrown much light on the state of navigation, geography, and commerce among the Romans in his time.