The returning tide of prosperity after the Revolution has left one mark in the Morris dwelling on the south side of Eighth, between Locust and Walnut, type of the wealthy home of the day. The biggest of the period was Robert Morris’s, on the site of the Press Building, left as his “folly.” The peak-roofed house in roomy squares now gave way for thirty years to the house built flush to the street, which in the generation between 1790 and 1820 spread the growing city up to Tenth Street or so, and of which many are left. With this growth dwellings pushed beyond South on one side and beyond Vine on the other, the fringe of the city limits becoming an Alsatia still apparent, mechanics’ homes crowding just beyond as they still do, until met north and even south by more pretentious dwellings. In this thirty years the city grew from 42,000 to 108,000, and it faced first the problem to which only the American and Australian city has proved fully equal in all the round of semitropical summers north or south of the equator. The city, as it inherited from England its city government, had also inherited from there its well-water supply, its surface drainage, its slovenly streets, its practice of crowding the homes of the poor on back lots, so as to fill the area on which they stood with unsavory wynds, and its habit of intramural interment and intramural slaughter-houses, all which, even the Latin cities of two thousand years ago, taught by hotter summers, had outgrown. In the tepid temperature and light but even rain-fall in England these worked few ills until the middle of this century. Under our torrid summer, our tropical rain-fall, and our swift changes, all these things meant disease and death, and the unconscious problem which faced the city a century ago and left its mark on the map was recorded in yellow fever, born of water-supply and filth together with overcrowding, and all the evils of bad water and overcrowding.