However defective may be the condition of an iron soil-pipe, vertical or horizontal, it is perfection itself compared with the usual state of a drain laid under the cellar floor; and here is a point where the least experienced inspector of house drainage cannot be mistaken. Under all circumstances, at least in all work hitherto executed, he should demand as absolutely necessary that the drains under the cellar floor be removed, that the earth which has been fouled by the leakage of its joints and its breaks shall be taken out to the clean untainted soil below, and refilled with well-rammed pure earth or with concrete, the drainage being carried through a properly-jointed iron pipe above the pavement, and preferably with a fall from the ceiling of the cellar to near the floor at the point of outlet--in full sight for the whole distance. It sometimes happens that the necessity for using laundry-tubs or other vessels in the cellar makes the retention of an underground course imperative. When retained, the drain should be of heavy cast iron with most securely leaded joints tested under a head of several feet. When found to be tight and secure, it should not be, as ordinarily recommended, left in an open channel covered with boards or flags and surrounded by a vermin-breeding, unventilated and uninspected space, but closely and completely imbedded in the best hydraulic cement mortar. Its careful testing before this {223} enclosure is of course the only condition under which the work can be permitted.