When the London fog is gray we cannot see him very far off, for he, too, is gray from head to foot with ash-dust, and as he approaches us he comes out of the mist like a phantom, though in reality he is a substantial, square-built, deep-chested fellow, shod with enormous Bluecher shoes (the soles of which are bright with nails), and clad in a loose blouse and trousers, that are tied up about the knees. The blouse is open at the chest, and is lifted to the waist by his big, brown hands, which are tucked in his trouser pockets, and his head is covered by the kind of hat that sailors call a sou'wester. His only ornament is a pair of ear-rings; and with his head thrown back he saunters along the street by the side of his cart, repeating in measured tones his cry, "Dust-oh-oh! dust-oh!" Now and then he stops at a house, and his mate--he has a mate, who is as much like him as pea is like pea--descends into the cellar, bringing forth the ashes and refuse that have accumulated in twenty-four hours, and when the cart, which is a square, box-like affair, is filled he starts for home with his load. What a queer home it is! It is on the outskirts of the city, far away from the finer streets and buildings. A large space of ground is as gray and dusty as an African or Western desert, and is broken by mounds of ashes, some of which are only a few feet high, while others are almost as high as houses,--quite as high, in fact, as the dismal little shanties on the edge of the reservation in which the dust-man and his fellows live. Other carts and other dust-men are constantly coming and going, dumping one load and then returning to the city for another, and as soon as a load is dumped it is attacked by a crowd of men, women and children, who with shovels, rakes and hooks, turn it over and over, and raise stifling clouds of dust. The reader may think that the collections made by the dust-man are valueless, but such is not the case. There are more than 300,000 inhabited houses in London, consuming more than 3,500,000 tons of coal a year, and besides the ashes from this great quantity of fuel, the dust-man gathers the other refuse of the houses. He is employed by a contractor, who agrees with the corporation to remove the ashes, etc., out of the city, and the contractor divides every load into six parts, as follows: Soil, or fine dust, which is sold to brick-makers for making bricks and to farmers for manure; brieze, or cinders, sold to brick-makers for burning brick; rags, bones and old metals, sold to marine-store dealers; old tin and iron vessels, sold to trunk-makers for clamps; bricks, oyster and other shells, sold for foundations and road-building; and old boots and shoes, sold to the manufacturers of Prussian blue. Sometimes, much more valuable things than these are found, and the reader may remember the romance that Charles Dickens made out of a London dust-man--"Our Mutual Friend."