The knowledge connected with the population was constantly increasing; and, though it was imperfect enough, still it was in advance of our previous information. In 1801 an approximation was made to that of London, which was supposed to be 864,845; and when it is remembered that Captain Graunt, so early as 1664, calculated it at 384,000, the numbering of the people in 1801 was no small benefit. In 1811, when a second census was taken, the population was stated to be 1,009,546; and a further increase was declared in 1821, when the population showed itself as 1,225,694. These calculations were not effected without difficulty, and many objections were made by good but narrow-minded men, who, from press and from pulpit, did not fail to remind our rulers that David was rebuked by the prophet, and punished by God, for attempting to do that which they had done. The health of London was also improved. It was estimated that the introduction of vaccination had increased the mean duration of human life about 3-1/2 years. There had been a great advance in medical skill. Discoveries in chemistry had been brought to bear upon disease. The arrangements of our hospitals had enabled students to graduate under men of distinguished attainments; the discipline of the medical school had been increased; and, though ignorance was often in the ascendant, and quackery was encouraged as a revenue to the state, men--somewhat different to those who were licensed to kill in the days of Fielding and of Smollett--were employed in invigorating the constitutions and prolonging the lives of their fellow-countrymen. We must not also forget, that by 1825 a vast improvement had occurred in the manners and habits of social life. Our fathers still remember their visits when the bottle kept so constant a round that few remained sober; when to be asked to a dinner-party was to be asked to get intoxicated; when two and three-bottle men boasted their acquirements; when the wild orgy disgraced humanity, and the wild debauch destroyed life. We of the present day boast of this improvement to our children, and whatever new vice may have usurped the place of the old, it is, at least, less open in its defiance, and less baneful in its results. When Petty first published, the streets were confined, cleanliness was disregarded, refuse and offal accumulated in the highways, and ventilation was laughed at. There may still be many receptacles of filth in London, but they do not meet us in our daily avocations. The kennels of Southwark do not run blood two days in every week, as they did in the last century; nor are hogs “bred, kept, and fed,” in our populous neighbourhoods. If, therefore, there were any thing in the advance of chemistry, in draining, in ventilation, in more wholesome living, in the absence of open debauchery, it followed that there would be a considerable decrease in the rate of mortality. From 1700 to 1780, the deaths averaged about one in thirty-eight of the existing