Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
In a financial point of view the state revenues of Carthage doubtless far surpassed those of Rome; but this advantage was partly neutralized by the facts, that the sources of the Carthaginian revenue--tribute and customs--dried up far sooner (and just when they were most needed) than those of Rome, and that the Carthaginian mode of conducting war was far more costly than the Roman.
In Their Military System
The military resources of the Romans and Carthaginians were very different, yet in many respects not unequally balanced. The citizens of Carthage still at the conquest of the city amounted to 700,000, including women and children,(10) and were probably at least as numerous at the close of the fifth century; in that century they were able in case of need to set on foot a burgess-army of 40,000 hoplites.
10. Doubts have been expressed as to the correctness of this number, and the highest possible number of inhabitants, taking into account the available space, has been reckoned at 250,000. Apart from the uncertainty of such calculations, especially as to a commercial city with houses of six stories, we must remember that the numbering is doubtless to be understood in a political, not in an urban, sense, just like the numbers in the Roman census, and that thus all Carthaginians would be included in it, whether dwelling in the city or its neighbourhood, or resident in its subject territory or in other lands. There would, of course, be a large number of such absentees in the case of Carthage; indeed it is expressly stated that in Gades, for the same reason, the burgess-roll always showed a far higher number than that of the citizens who had their fixed residence there.
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Reference address : https://www.ellopos.net/elpenor/rome/3-01-carthage.asp?pg=41