As Eassie has pointed out, there is much to be considered in the arrangement of rain-water pipes from a sanitary point of view, where a separator and storage tank are not in use, because the foul air delivered from them is sucked into the rooms near the roof, on which the sun’s heat pours. A fire lighted in a room develops the same danger when the rain-water pipe terminates near the windows of the room. Another danger accruing from rain-water pipes which connect directly with the drain is due to the fact that the joints of the iron rain-water pipes are seldom air-tight, and foul air is therefore often driven or sucked into the rooms when the windows are open. It is easy to imagine how dangerous this must be in houses which have been fitted up with iron (or even lead) rain-water pipes running down the interior walls, and having their terminations close to a dormer window, skylight, or staircase ventilator on the roof, with the foot of the rain-water pipe taken direct into a drain leading to a town sewer. But the risk is greatly increased when the rain-water pipes are connected with a closed cesspool, to which the rain-water pipe is acting as a ventilator. When rain-water pipes deliver into the drain directly, they are often made to act as soil pipes from the closets, in which case the evil is intensified. The soil from the closets is apt to adhere to the interior of the pipe, generally on the side opposite to that traversed by the rain-water, and the poisonous smell escapes at any bad joints and always at the roof orifice. When the rain-water pipe is of cast iron, other sources of danger are present if the pipe is used also for conveying soil from a closet. Unless the rim of the soil pipe from the closet is joined to the rain-water pipe by a proper cast-iron socketed joint, the connection must be made by means of a piece of lead pipe which receives the soil pipe, and the joint between the lead soil pipe and the upper and lower parts of the cast-iron pipe cannot be properly soldered. Here sometimes grievous calamity follows cases where the combined pipe is ventilating the drain and sewer; the pipe joints are frequently open, and when the windows are unclosed for ventilation the foul air is whisked into the house. Eassie insists that it is cheaper to owner and dweller alike to have a separate soil-pipe erected at first. [Illustration: 5. Outlet of Rain-water Pipes.]