Hume seems so far from having himself contemplated the application of philosophical skill to the organization of large masses of human beings, that we frequently find in his writings and in his letters, remarks on the growth of cities, sometimes speaking of certain limits which they cannot pass, at other times noticing, in a tone of despondency, the rapid progress of London, as if it were exceeding those bounds within which mankind can be kept under the dominion of law and order. In the essay on the Populousness of Ancient Nations, he says, "London, by uniting extensive commerce and middling empire, has perhaps arrived at a greatness, which no city will perhaps be able to exceed;" and he fixes this number at 700,000 inhabitants,--saying farther, "from the experience of past and present ages, one might conjecture that there is a kind of impossibility that any city could ever rise much beyond this proportion." London must then have been considerably under the population he thus assigns to it, and it had not probably reached that number of inhabitants twenty-four years later, when we find him, oppressed by the disease of which he died, saying in a letter to Smith, "should London fall as much in its size as I have done, it will be the better. It is nothing but a hulk of bad and unclean humours." During Hume's lifetime, the metropolis had been frequently outraged and intimidated--on some occasions almost desolated, by mobs of city savages; beings far more formidable and brutal than the savages of the wilderness. At the time when he published his Political Discourses, it contained bands of robbers, who followed their trade as openly as the brigands of the Abruzzi, committing robberies and murders in the middle of the city, in open day. Those who saw the city increasing in size, while it retained these evil characteristics, naturally looked upon it as a cancer, near the most vital part of the empire, and lamented accordingly its waxing prosperity and bulk. But its size was not the cause of the evil. It is now three times as populous as when Hume wrote, yet, with much poverty, much vice, and much ignorance, it is not the same diseased and dangerous mass it then was. The comparative sober quietness of the streets,--the well ordered police,--the facilities for discovering persons who are sought after, without their being subjected in their movements to any control, inconsistent with British liberty,--are all, when practised on so large a scale, indications that human genius has great capacities for organization; and they may be, for aught that can be seen to the contrary, only the initial movements, which future generations will carry to far more wonderful results.