A second method is to _sift and sort the refuse_, separating by means of sieves the finer ash and dust from the coarser parts. This is usually carried out in a large dust-yard adjoining a river or railway-siding. The “breeze,” consisting of cinders and coals, along with the fine ash, are sold to brickmakers; the “hard core,” consisting of clinkers, broken crockery, etc., is used for road making; and the “soft core,” consisting of animal and vegetable refuse, to which is often added stable manure, is sold for manure. Iron, tin, paper, rags, bottles, and corks are separately collected and sold. This disgusting process, often carried on by women, is now gradually being disused. A third method is to _cremate the house refuse_. This has been done to a large extent by burning the house refuse for making bricks (page 124). This method of slow and imperfect combustion necessarily involves a nuisance. A more elaborate means of securing the same end is by the modern =Destructor=, which has been gradually brought towards perfection. A destructor is a large furnace, in which, after the fire has been first lit, the combustible matter in the house refuse suffices to keep it alight. Various mechanical devices are in use for emptying the trucks of house refuse on to the fires without handling it, for clearing out of the fire the inorganic refuse, and for ensuring sufficiency of draught. The amount of draught has in the older destructors been dependent upon the height of the chimney. In some more recent destructors the same end has been more efficiently secured by injecting a steam blast into the furnaces. A temperature of about 2,000° F. is reached in certain parts of the destructor, the rapid draught ensuring enormous heat. In view of the possibility of a portion of the smoke not being completely burnt, a second “fume cremator” is often provided, through which the products of combustion in the furnace are passed. The fuel in the “fume cremator” is coke. Besides incomplete combustion of combustible material, which is rare when the fume cremator is provided, the escape of fine dust up the chimney requires to be guarded against. This is partially prevented by ledges near the bottom of the chimney. In a destructor the house refuse is reduced to about one-third of its original bulk, the residue being innocuous clinker, metallic refuse, and dust. This material can be utilised for making roads, and in the manufacture of mortar. The waste heat of the destructor has been partially utilised for various purposes. This method of disposal of house refuse is usually the best available for large towns, and offers the additional advantage that no nuisance is caused by the deposit of offensive material in neighbouring districts. CHAPTER XXX. POSITION OF THE HOUSE.