All the best manuscripts of Pliny read the passage as here cited, and fix the compass of the walls of Rome to be thirteen miles. The question is, what Pliny means by 30,775 paces, and how that number was formed? The manner in which I conceive it is this: Rome was a semicircular area of thirteen miles circumference. The Forum, and consequently the Milliarium, we know was situated on the banks of the Tiber, and near the centre of the circle, or upon the diameter of the semicircular area. Though there were thirty-seven gates to Rome, yet only twelve of them had straight streets, leading from them to the Milliarium. Pliny, therefore, having assigned the circumference of Rome, and knowing that that alone was not sufficient to give us a just notion of its surface, uses this further method. He supposes all the streets leading from the Milliarium to the twelve gates to be laid together into one straight line, and supposes we run along that line so as to count each gate once, in which case, he says that the whole line is 30,775 paces; or, in other words, that each street or radius of the semicircular area is upon an average two miles and a half, and the whole length of Rome is five miles, and its breadth about half as much, besides the scattered suburbs. Père Hardouin understands this passage in the same manner, with regard to the laying together the several streets of Rome into one line in order to compose 30,775 paces; but then he supposes that streets led from the Milliarium to every gate, and that no street exceeded 800 paces in length. But (1) a semicircular area whose radius was only 800 paces could never have a circumference near thirteen miles, the compass of Rome as assigned by Pliny. A radius of two miles and a half forms very nearly that circumference. (2) There is an absurdity in supposing a city so built as to have streets running to its centre from every gate in its circumference. These streets must interfere as they approach. (3) This diminishes too much from the greatness of ancient Rome, and reduces that city below even Bristol or Rotterdam.