Twenty years ago, the main sewers of London, having their outlets on the river side, were completely open, and it was lawful to enter them to search for valuables, but since then so many people have died of the gases, or have lost themselves in their noxious recesses, that a law was at last passed, by which persons entering the sewers to explore them, unless they were employed as workmen, became amenable to imprisonment, and at present the law is strictly enforced. [Sidenote: SEWER HUNTERS.] Formerly, when the spring tides in the Thames began, it was of common occurrence for the waters to dash into the sewers, sweeping everything in their way, and very often engulfing the workmen, or others engaged illegally in searching the sewers; and days after one of these tidal floods had occurred bodies of drowned and disfigured men would be vomited from the mouths of the sewers. Now, however, this is changed, and hanging iron doors, with hinges, are affixed to the mouths of the sewers, and are so arranged that when the tides are low the iron doors are forced open by the rubbish and wet refuse which is emptied into the Thames, and when the tides rise the volume of water forces the doors back, and the river cannot enter the sewers. There are two or three hundred men in London, who earn a living by working in the sewers. These men, though there is a law against the practice, search the sewers, night and day, for old iron, rope, metal, money, or whatever is of value to the finder. They are called "Toshers," or "Shore-men," and are, in some things, very like the "mud-larks," who frequent the river sides. Some of these men are very fortunate at times, and succeed in obtaining good prizes from the black, stinking mud of the sewers. Gold watches, silver milk-jugs, breast-pins, bracelets, and gold rings, are obtained by them. These sewer hunters, however, do not trouble themselves to collect coal, wood, or chips, as is the case with the mud-larks. There are better prizes for them, and accordingly, they do not waste their time on such trifles. The Sewer-Hunter, before penetrating a sewer, provides himself with a pair of canvas trousers, very thick and coarse, and a pair of old shoes, or high-topped boots--the higher the legs the better. The coat may be of any material, only it must be of heavy fabric, and there are large pockets in the sides, where articles may be crammed at will. They carry a bag on their backs, these sewer-hunters, and in their hand a pole, seven or eight feet long, on one end of which is fastened a large iron hoe to rake up rubbish. Whenever they think the ground is unsafe, or treacherous, they test it with the rake, and steady their steps with the staff.