also the roof, in order to show the roof connection for this stack, and also for the one in Fig. 7 we show by a note how they are to be run.

Fig. 7 represents an elevation of the water closet located in the cellar, and the toilet room located on the first floor. The stack serving the toilet room passes up on one of the cellar piers, as shown by the cellar plan, and this fact is also shown on the elevation. The stack is run on the first floor through the closet, and also through closet on the two floors above. This stack is designated on the several floor plans as stack B. Now if the student will measure with his dividers from the side of the first floor plan (Fig. 2) to the center of this stack, and then do the same thing on the second floor plan (Fig. 3) he will find that on the latter the stack is located further to the left. This is in order that the stack may be run in a convenient place, and at once shows that at the second floor the stack

FIG. 9

Main Stack

ELEVATION Room

served by stack C on the second and third floors. In this elevation we have shown the main line of back air pipe connected at its lower end, back into the stack, which makes a better piece of work than

The only other point in connection with Fig. 8 that we wish to bring out is the view which is obtained of the two lavatory traps. The view of these two fixtures is taken in the direction of the

do not stand so that their full shape appears, but as shown in Fig. 8. While strictly adhering as a general thing to the exact appearance of an object of this nature in our work, it will often be found of advantage to depart from this rule, and in such a case as this, to show the shape of the trap. Instead of showing the two bath rooms on the second and third floors in one elevation, we show each separately in Figs. 9 and 10. This is done simply to save space. The third floor or servants' bath room is viewed along the direction of arrow M in Fig. 4, which gives us a very clear view of the work. In this view the main back air line stands in front of the main stack, and we attach a note showing where the connection of the former with the latter may be found. In the same way we show a note on Fig. 5 indicating where the upper connection between these two lines of pipe may be seen. As this shows, a note of this kind may often take the place of the drawing itself. The view shown by Fig. 10 is taken along arrow