13,639. Schulz, R. July 4. Superheaters, steam. - In watertube boilers of the type shown, a portion of the space usually occupied by water tubes is occupied by superheater tubes k, a certain number of water tubes being, however, retained, sufficient to protect the superheater from the direct heat of the fire. The superheater tubes k may be in the form of loops, as shown in Figs. 2 and 4, or they may be bent or straight tubes connecting independent drums, as shown in Fig. 9; or one independent drum only may be employed, or a portion of the water drum a may be divided off to serve as a connection for the superheater tubes. Water tubes are shown at c, Fig. 2. In another arrangement, sinuous tubes connect two short horizontal drums, placed one above the other. The tubes and the baffle-plates in connection with them may be arranged to cause the furnace gases to pass up and down, or horizontally to and fro among the superheater tubes ; a damper is preferably provided as shown at n, Fig. 4. The application of the invention to boilers having two or more water drums and one or two steam drums is illustrated in the Specification. Arrangements of valves and connecting-pipes to enable one superheater to serve one or several boilers are described.