Next inside the trap is the vent pipe _E_, that extends to the surface of the ground. In this case it is just outside the basement wall. The top is covered with a metal cap. Another arrangement often made to accomplish the same purpose is shown in Figs. 61 and 62, where a piece of soil pipe in the form of a bend is made to take the place of the cap. Inside the basement and extending up through the partition walls to the roof is the _waste stack_ or soil pipe _A_. This pipe as is explained in detail later, is made of cast iron and is put together with calked lead joints. The top of the stack at the point where it passes through the roof is shown in Fig. 59. In extending through the roof the pipe _A_ must make a water-tight joint to prevent water from leaking through. This is accomplished by means of the metal plate _D_, which is set under the shingles and the piece _C_, that is soldered to _D_. The joint between _C_ and _A_ is best made with lead the same as the other joints of the stack. In the case of very high stacks, the bottom should be supported by a pier or iron pipe rest. Besides being supported at the base the stack should be secured to the side walls or floor beams at each floor. This is to keep the pipe from moving out of place and the consequent opening of joints. [Illustration: FIG. 59.--Detail of soil pipe connection.] [Illustration: FIG. 60.--Cross-section of cellar-drain.] All of the waste pipes from the bathroom, kitchen and basement drain into the waste stack. The cellar drain for draining the basement is shown at _T_ in Fig. 58. It also appears in detail in Fig. 60. The plate _B_, in the latter figure, is set flush to the surface of a depression in the floor that serves as a collecting point for water. The floor is constructed to drain toward this point. The plate is perforated to let the water through and is generally hinged so that in case of stoppage the cover may be raised. The bell-shaped piece under the cover surrounds the piece _C_, to form a water seal when the level of the water is at _A_. In addition to this water seal there is generally a trap between the drain and the sewer as shown in the drawing. The method of connecting the bathroom waste pipes with the stack is shown in Fig. 99 and will be described later. All of the sewage of the house is emptied into the stack by the most direct route, and from the stack it is conducted as directly as possible into the sewer. From the drawing it will be seen that all openings to the sewer are sealed in two separate places, once at the outlet to prevent the air from the street sewer entering the house drain _G_, and again at each opening to prevent escape of the sewer gas from the drain into the house. [Illustration: FIG. 61. FIG. 62. FIG. 61.--House drain with outside vent, and running trap placed inside the basement wall. FIG. 62.--House drain with outside vent, and running trap placed outside the basement wall.]