It is a fallacy to say that the New River now exclusively _prevents_ infectious disorders by the distribution of its water through the City, as it is well known to have been introduced to the houses very many years before 1665. It is to the improved dwellings composed of brick, the wainscot or papered walls, the high cielings, the boarded floors, and large windows, and cleanliness, that we are indebted for the general preservation of health since 1666. From that auspicious year the very existence of the natives of London improved; their bodies moved in a large space of pure air; and, finding every thing clean and new around them, they determined to keep them so. Previously-unknown luxuries and improvements in furniture were suggested; and a man of moderate fortune saw his house vie with, nay superior to, the old palaces of his governors. When he paced his streets, he felt the genial Western breeze pass him, rich with the perfumes of the country, instead of the stench described by Erasmus; and looking upward, he beheld the beautiful blue of the air, variegated with fleecy clouds, in place of projecting black beams and plaster, obscured by vapour and smoke. But there were other blessings, which he thought not of, that are attained by his successors; and those I shall proceed to describe chronologically, after introducing the assertions of M. de Grosley on the state of London with respect to Cleanliness _circa_ 1750. That gentleman observes, in his Tour to London, that "the plate, hearth-stones (generally marble), moveables, apartments, doors, stairs, the very street-doors, their locks, and the large brass knockers (almost exclusively iron at present), are every day washed, scowered, or rubbed. Even in lodging-houses, the middle of the stairs is often covered with carpeting, to prevent them from being soiled. All the apartments in the house have mats or carpets; and the use of them has been adopted some years since by the French." The streets of London must have been dangerously dark during the winter nights before it was burnt: lanterns with candles were very sparingly scattered, nor was light much better distributed even in the new streets previous to the last century.