The _Drainage_ of London was a matter barely understood at all, and in no wholesome sense practised, till some time after the Board of Works was formed, in 1855, when their best efforts to check a rapidly growing evil—viz., the casting of London’s poisonous sewage into the Thames at our very doors—were called into play. The estimated cost of one of the most colossal schemes of modern times was, at its outset, put down at something over three millions; and when the vast plan for main drainage was commenced, in 1859, a sanitary revolution began. A far greater sum, however, must be expended ere the idea is wholly carried out. It is obviously out of our power, in our limited space, to do anything more than give the reader a mere rough notion of the good to be done and the difficulties to be overcome. The plan was to construct some 70 odd miles of gigantic sewers on either side of the Thames. The north side of the river has three different lines of sewers, which meet at the river Lea, and thereafter go along, in one huge embankment, to Barking Creek, on the Thames, 14 miles below London Bridge. With certain differences, the sewage of the south side of the Thames is amenable to the same kind of treatment. By some returns, furnished in June, 1870, by the engineer of the Metropolitan Board of Works, it appears that the average daily quantity of sewage pumped into the river Thames at Crossness was 170,934 cubic metres, and at Barking 152,808 cubic metres—equivalent to about as many tons by weight. That quantity, of course, will every year, as London grows, increase. As the sewers on the north side of the river get more near to the sea, they can be seen. The south side sewers are nearly all out of sight. As the tide flows, the filth of London, by their means, is poured into the water. As it ebbs, the sewage is carried out to sea. Powerful steam-engines, for pumping up sewage from low levels, are used as they are required. The clerk of the Metropolitan Board of Works, who may be seen at Spring Gardens, Charing Cross, will, we should fancy, oblige any gentleman with engineering proclivities with an order to view what has already been accomplished by marvellous ability and enterprise,—whose results can in no fair sense gain anything like fair appreciation without personal inspection. London is _Lighted_ by sundry joint-stock gas companies; the parishes contract with them for street lights, and individuals for the house and shop lights. Gas was first introduced into London, in Golden Lane, in 1807; in Pall Mall in 1809; and generally through London in 1814. There are something like 2,500 miles of gas-pipes in and about London. The first of the public _Baths_ and _Wash-houses_ was established near the London Docks in 1844. The number, of course, has vastly increased. Many of them are maintained by the parish authorities, and are very cheap.