1.  The empire, at the death of Augustus, was bounded on the west by the Atlantic ocean, on the north by the Rhine and the Danube, on the east by the Euphrates, and on the south by the deserts of Arabia and Africa.  The only addition which it received during the first century was the province of Britain:  with this addition it remained till the reign of Trajan.  That emperor conquered Dacea, and added it to the empire:  he also achieved several conquests in the east; but these were resigned by his successor Adrian.  At this period, therefore, the Roman empire may be considered as having attained its utmost limits.  It is impossible to ascertain the number of people that were contained within these limits.  In the time of Claudius the Roman citizens were numbered; they amounted to 6,945,000:  if to these be added the usual proportion of women and children, the number will be encreased to about 20,000,000.  If, therefore, we calculate, as we may fairly do, that there were twice as many provincials as there were citizens with their wives and children, and that the slaves were at least equal in number to the provincials, the total population of the Roman empire will amount to 120,000,000.

Our ideas of the vastness and wealth of the empire will be still farther encreased, if we regard the cities which it contained, though it is impossible to decide in most instances the extent and population of many places which were honoured with the appellation of cities.  Ancient Italy is said to have contained 1197, Gaul 1200, of which many, such as Marseilles, Narbonne, Lyons, &c. were large and flourishing; Spain 300, Africa 300, and Asia Proper 500, of which many were very populous.

2.  All these cities were connected with one another and with Rome itself by means of the public highways:  these issuing from the forum, traversed Italy, pervaded the provinces, and were terminated only by the frontiers of the empire.  The great chain of communication formed by means of them from the extreme north-west limit of the empire, through Rome to the south-east limit, was in length nearly 4000 miles.  These roads were formed in the most substantial manner, and with astonishing labour and expence; they were raised so as to command a prospect of the adjacent country; on each side was a row of large stones for foot passengers.  The miles were reckoned from the gates of the city and marked on stones:  at shorter distances there were stones for travellers to rest on, or to assist those who wished to mount their horses:  there were cross roads from the principal roads.  The care and management of all the roads were entrusted only to men of the highest rank.  Augustus himself took charge of those near Rome, and appointed two men of praetorian rank to pave the roads:  at the distance of five or six miles houses were built, each of which was constantly provided with forty horses; but these could only be used in the public service, except by particular and express authority.  By means of the relays thus furnished, the Romans could travel along their excellent roads 100 miles a day:  they had no public posts.  Augustus first introduced public couriers among the Romans; but they were employed only to forward the public despatches, or to convey public intelligence of great and urgent importance.